Derm

Question 1

Skin anatomy/physiology - general

Answer 1

1. Epidermis
   a. Mainly composed of keratinocytes
   b. 5 Layers
   c. Takes 28 days to get from basal layer to shedding from stratum corneum
   d. Other cells: melanocytes (derived from neural crest, contain pigment), Merkel cells (mechanosensory receptors) + Langerhan cells (dendritic cells)
2. Dermis
   a. Composed of fibroblasts – synthesize collagen, elastic fibres and mucopolysaccharides
   b. Layers
   i. Superficial papillary layer (more cellular)
   ii. Deep reticular layer (more collagen and elastic fibres)
   c. Other structures: blood vessels, lymphatics, mast cells, sweat glands, sebaceous glands
3. Subcutaneous tissue
4. Appendageal structures
   a. Derived from aggregates of epidermal cells that become specialized during embryonic development
   b. Hair follicles
   i. Lanugo – thin, downy hair (of premature neonates)
   ii. Vellus – normal hair on all of body, unpigmented
   iii. Terminal – long and coarse hair on scalp, eyebrows etc
   c. Sebaceous glands
   i. Present everywhere except palms, soles and dorsa of feet
   ii. Ducts open into hair follicles, lips, prepuce, labia minora
   d. Apocrine glands
   i. Glands of axilla, areola, perianal, genital and periumbilical region
   ii. Enlarge and secrete in response to androgenic activity in puberty
   e. Eccrine sweat glands
   i. All over, including palms and soles
   ii. Involved in thermoregulation

Question 2

Erythema toxicum neonatorum - general

Answer 2

a. Common pustular disorder occurring in 20% of neonates in the first 72 hours of life
i. Most prominent on day 2
b. Caused by immaturity of the pilosebaceous follicles
c. More common in neonates with higher birthweight and greater gestational age
d. Clinical manifestations
i. Well baby
ii. Usually appear 24-48h but may be present at birth
iii. Multiple erythematous macules and papules (1 to 3 mm)  rapidly progress to pustules on erythematous base
iv. Distributed over the trunk and proximal extremities, sparing the palms and soles
v. Usually resolves in 5-7d, although it may wax and wane before complete resolution
e. Investigations = nil required, if biopsy Gram stain full of eosinophils

Question 3

Neonatal acne/6 week eruption - general

Answer 3

Neonatal cephalic pustulosis

a. Otherwise known as ‘milk spots’ or ‘neonatal acne’
b. Pityrosporum (malessezia) folliculitis = active oil glands colonize with yeast
c. Occurs in 20% of infants
d. Mean age of onset 3 weeks
e. Fades as sebaceous glands settle to quiescent childhood levels
f. Occurs as symmetrical eruption in well baby
g. Treatment
i. 2% ketoconazole cream or ketoconazole shampoo diluted 1 in 10 applied by a cotton bud
ii. Twice per day results in rapid clearing

Question 4

Infantile acne - general

Answer 4

a. Uncommon and distinct entity from neonatal cephalic pustulosis
b. Presents at 3-4 months of age
c. Results from hyperplasia of sebaceous glands secondary to androgenic stimulation
d. More common in boys
e. More severe than cephalic pustulosis – typical acneiform lesions
f. Treatment as can cause scarring (unlike neonatal cephalic pustlosis)

Question 5

Miliaria - general

Answer 5

Sweat rash
Miliaria crystallina affects up to 9% of neonates, with the mean age of 1 week.

a. Common finding in newborns, especially in warm climate
b. Caused by accumulation of sweat beneath eccrine sweat ducts that are obstructed by keratin at the level of the stratum corneum
c. Miliaria rarely is present at birth
d. It usually develops during the first week of life, especially in association with warming of the infant by an incubator, occlusive dressings or clothing, or fever
e. It is characteristically distributed on the face, scalp, and intertriginous areas

Question 6

Infantile acropustulosis - general

Answer 6

a. Occurs in black males 2-10 months
b. Discrete erythematous papules that become vesiculopustular within 24 hours
c. VERY itchy, most common on palms and soles
d. Occurs in episodes every 2-4 weeks for 7-14 days
e. Histology: neutrophils +/- eosinophils
f. Treatment = topical steroids and antihistamines
g. Etiology unknown

Question 7

HSV/VZV infection

Answer 7

HSV

i. Three patterns of disease
1. Localised to the skin, eye and mouth
2. Localised CNS
3. Fulminant, disseminated

ii. Skin lesions majority (all 3 above patterns)
1. Lesions not present at birth, 6-13 days
2. 1-3mm vesicles and erythematous papules – crust, erode
3. Usually occur on scalp or face, trunk or buttocks (breech)

VZV

i. Days after birth
ii. Develop fever then vesicular rash, usually heals 7-10days
iii. Can get disseminated disease – pneumonia, hepatitis, meningoencephalitis
iv. High mortality

Question 8

Staphylococcal pustulosis

Answer 8

i. Develops postnatally
ii. Pustules, erythematous papules, honey colored crusts – easily ruptured resulting in superficial erosions and honey-coloured crusts
iii. Lesions found in areas of trauma – diaper, circumcision, axillae, periumbilical

Question 9

Staph scalded skin syndrome

Answer 9

i. Newborns especially susceptible to dissemination of exfoliative toxins, which cause cleavage of desmoglein 1 (anchor keratinocytes to one another)
ii. Rarely seen at birth
iii. Onset day 3-7 of life
iv. Febrile, irritable, diffuse blanching erythema beginning around mouth
v. Flaccid blisters appear 1-2 days later in areas of stress – flexural, buttocks, hands, feet
vi. Gentle pressure results in separation of epidermis (Nikolsky’s sign) – sometimes whole epidermis effected
vii. Desquamation until healing

Question 10

Neonatal strep infection (Derm)

Answer 10

i. May mimic infections caused by staphylococci
ii. GBS most commonly cause neonatal sepsis
iii. Skin lesions such as bullae, erosions and honey-coloured crusts occur rarely
iv. May be present at birth or develop later

Question 11

Neonatal listeriosis (derm)

Answer 11

i. Clinical manifestations can occur early (<7 days) or late (>7 days)
ii. Both forms can present with meningitis and signs of septicaemia
iii. Infants with the early form often have multiple pustules on the skin and mucous membranes

Question 12

Congenital syphilis

Answer 12

i. Early manifestations variable
ii. Haemorrhagic bullae and petechiae start on the palms and soles and spread to the trunk and extremities are pathognomonic of congenital syphilis
iii. If ulcerative highly contagious
iv. May also have desquamative dermatitis involving palms and soles

Question 13

Neonatal candidiasis

Answer 13

i. Develops in first week of life
ii. Affects moist, warm regions and sin folds
iii. Confluent erythema with multiple tiny pustules or discrete, erythematous papules and plaques with superficial scales
iv. Satellite lesions are typically noted
(The term “satellite lesions” is used in many conditions in dermatology, generally to describe smaller lesions near the edges of a principal lesion)

Question 14

Congenital sucking blisters

Answer 14

a. Diagnosis of exclusion
b. Noninflammatory, oval, thick-walled vesicles or bullae that contain sterile fluid
c. Unilateral or bilateral, typically are located on the dorsal or radial aspect of the wrists, hands, or fingers of neonates who are noted to suck excessively at the involved regions
d. DDx = HSV, bullous impetigo, congenital syphilis or candidiasis, neonatal SLE, and hereditary bullous diseases

Question 15

Epidermolysis bullosa

Answer 15

a. Group of inherited diseases characterized by skin fragility and blister formation caused by minor skin trauma
b. EB is broadly classified into four groups, based upon the level at which the blisters form
i. EB simplex
ii. Junctional EB
iii. Dystrophic EB
iv. Kindler syndrome

Question 16

Aplastic cutis congenital

Answer 16

1. Key points
   a. Rare, Heterogenous group of congenital disorders characterised by focal or widespread absence of skin
   b. Involves dermis + epidermis
   c. In majority of cases it is an isolated finding
2. Associations
   a. T13
   b. Cleft lip and palate, defects of hands and feet
   c. Bart syndrome
   d. Congenital anomalies – abdominal wall defect, limb abnormalities, cleft abnormalities
3. Clinical manifestations
   a. Erosions present at birth
   b. Most commonly present on scalp
   i. <1cm, solitary, hairless skin defect on the scalp vertex covered with atrophic tissue or eschar
   ii. Grouped defects can also be seen
   iii. Surface may be covered with granulation tissue or may be ulcerated, eroded or scar-like
   iv. >80% are found on or near the midline between the anterior + posterior fontanelle
   v. 15-30% associated with defect in underlying bone and dura mater with exposure of underlying brain and sagittal sinus
   c. Re-epithelialises over months
4. Investigations
   a. Clinical diagnosis
   b. Additional evaluation
   i. Newborns with large scalp defects or membranous lesions may requiring imaging
5. DDx
   a. Obstetric trauma from forceps or fetal scalp electrodes
   b. Congenital Volkmann ischaemic contracture

Question 17

Incontinentia pigmenti

Answer 17

a. X-linked dominant multisystem
b. Caused by mutation of IKBKG/NEMO
c. Lethal in males in utero
d. Females
i. Staged cutaneous eruption
ii. Variable developmental abnormalities involving the teeth, hair, and nails
iii. Ocular and neurologic abnormalities

Stage 1: vesicubullous, erythema and blistering
Stage 2: verrucous, hypertrophic rash
Stage 3: hyperpigmented
Stage 4: atrophic/hypopigmented, alopecia

Question 18

Dermoid cysts and sinuses

Answer 18

a. Dermoid cysts = congenital SC lesions that are usually distributed along embryonic fusion lines of the facial processes within the neural axis
i. Most common location = overlying anterior fontanelle, the bregma (junction of coronal and sagittal sutures), upper lateral region of forehead, lateral upper eyelid, submetnal region
ii. Almost always present at birth although may be subtle and not noticed
iii. Small, slow-growing, asymptomatic rubbery subcutaneous nodules that are usually solitary
iv. Should be surgically excised due to risk of complications – infection, meningitis, erosion, damage to nasal bones, malignant degeneration (rare)

b. Dermal sinus tracts = may connect cysts to the skin surface or to underlying structures (eg. bone, CNS, paranasal sinuses)
i. Connections to CNS most frequent with midline or nasal dermoid cysts – occur in 25% of cases
ii. Midline lesions are often a marker of spinal dysraphism – should undergo CNS imaging
iii. Sinus tracts to the skin are usually detected when they become infected and drain purulent material

Question 19

Branchial cleft cyst

Answer 19

a. Arise from the first and second branchial arches
b. Commonly located anterior to the SCM on the lower third of the lateral neck
c. Often contain lymphoid tissue

Question 20

Thyroglossal duct cyst

Answer 20

a. Most common form of congenital neck cyst
b. Epithelial remnants of the thyroglossal tract
c. Midline neck mass at the level of the thyrohyoid membrane

Question 21

Subcutaneous fat necrosis - general

Answer 21

1. Key points
   a. Rare condition
   b. Affects newborns in first few weeks of life
   c. Term or post-term newborns
   d. Usually follows perinatal complications – birth asphyxia, hypothermia, MAS, FTT, forceps, maternal high BP or diabetes
2. Clinical manifestations
   a. Multiple firm non-tender SC nodules or large plaques
   b. Appear 1-4 weeks after birth
   c. Site = cheeks, buttocks, back and limbs, often over bony prominence
   d. Overlying skin may be erythematous
3. Complications
   a. Hypercalcaemia = irritability, anorexia, constipation, FTT, seizures
   i. Mechanism unknown
   b. Thrombocytopenia
   c. Hypoglycaemia
4. Treatment
   a. Supportive

Question 22

Milia

Answer 22

a. Superficial epidermal inclusion cysts
b. Laminated keratinized material
c. Scattered over face and gingivae  Ebstein’s purls

White dots, commonly on the nose

Question 23

Salmon patch

Answer 23

Naevus simplex

a. Small, pale pink vascular macules
b. Caused by vascular ectasia (dilation)
c. Most common the glabella (between eyebrows), eyelids, upper lid and nuchal area
d. Becomes more visible during crying
e. Usually fade and disappear completely

Question 24

Cradle cap

Answer 24

Seborrheic dermatitis

a. Probably analogous to dandruff in the adolescent/adult
b. Occurs from 1 week to 4 months
c. ? Contributed to by malasesezia infection
d. Appearance
i. ‘Greasy’ scale
ii. Generally not pruritic
iii. Ill-defined erythematous patches
iv. Overgrowth of hair follicles
e. Treatment
i. Not necessary
ii. Removal scale without irritating scalp – soap substitutes, olive oil, bath oil, may comb
iii. Ketoconazole shampoo if recurrent – nizoral, sebizole
iv. Salicylic acid creams only rarely require

Do not diagnose cradle cap after 4 months

Question 25

Scalp eczema

Answer 25

a. Do not diagnose cradle cap after 4 months
b. Scale is harsher, pruritis is common
c. Usually eczema elsewhere
d. Treatment
i. Treat as eczema elsewhere - use topical steroid ointments rather than lotions
ii. No role for anti-yeast therapy
iii. Salicylic acid will worsen

Question 26

Cutis marmorata

Answer 26

a. Mottling: lacy, reticulated rash

b. Represents an accentuated physiologic vasomotor response

Question 27

Harlequin colour change

Answer 27

a. Most common in LBW infants, often in newborn period
b. Due to imbalance in autonomic vascular regulation
c. Differential colour change when lying on side, with dependent half becoming red

Question 28

Mongolian spots

Answer 28

a. Blue/slate gray macular lesions
b. Present in > 80% of black, Asian and east Indian infants
c. Melanin containing melanocytes arrested during migration from neural crest to epidermis
d. Usually fade due to darkening of overlying skin

Question 29

Nappy rash

Answer 29

a. Irritant contact dermatitis = combination of heat, occlusion, urine and faeces
i. Much less common with better disposable nappies
ii. Secondary candida infection (thrush) much rarer – appears beefy red, well demarcated

b. Once broken down the natural barrier is disturbed as threshold of irritation is less
c. Classically spares the folds
d. Aims of management = prevent irritation, settle inflammation, treat secondary infection

e. Treatment
i. Use disposable nappies with frequent changes + nappy free time
ii. Wash with diluted bath oil using cotton balls or chux towels – dab rather than wipe
iii. Bath oil and no other irritants in bath
iv. Protection from urine/faeces
1. Protective barrier against irritants = should still be there at next change
2. Do not try to remove each change – adds to irritation
3. Individual preference in barrier creams = covitol, bepanthen, plain zinc cream, 10% olive oil in zinc paste; no preservatives, fragrances, antiseptic, essential oils
v. Settle inflammation
1. 1% hydrocortisone = sigmacort, egocort, dermoid
2. Should only require daily application
vi. Treat secondary infection
1. Add canestant/ daktarin with hydrocortisone if suspicious
2. Antifungal creams can be a little irritating
3. Have area swabbed if concerns

Question 30

Zinc deficiency (derm)

Answer 30

1. Key points
   a. Think zinc unusual eruption with diarrhoea
   b. Age of onset determines congenital or acquired
   c. Blood zinc may be inaccurate
   d. Clinical challenge useful
2. Aetiology
   a. Inherited – acrodermatitis enteropathica
   i. AR
   ii. Defect in absorption of zinc from GIT – 2-3% vs 27-64%
   iii. Breast milk protective – usually prevents following weaning
3. Presents LATER than acquired form
   b. Acquired
   i. Usually multifactorial
4. Prematurity – decreased stores, malabsorption, increased demand
5. Low breast milk zinc
6. Malabsorption
   ii. Historically, TPN major cause but now protective
7. Clinical manifestations
   a. Sharply demarcated, eroded eruption
   i. Symmetrical
   ii. May be vesicobullous
   iii. Distribution periorifacial plus extremities
   b. Diffuse alopecia
   c. Diarrhoea
   d. FTT
   e. Depressed mood, irritability
   f. Immunosuppression
   g. Cognitive/ motor delay
8. Investigations
   a. Blood zinc level
   i. Not an accurate measurement of stores (neither is hair or urine)
   ii. Many false positives and negatives
   iii. No good measure of zinc stores
   b. Low ALP
   c. Maternal breast milk zinc
9. Management
   a. Replacement
   iii. Therapeutic investigation
   b. Continue until weaned in acquired, lifelong in acrodermatitis enteropathica
   c. Differential diagnosis is a variety of other metabolic abnormalities
   i. ‘Acrodermatitis acidemica’
   ii. Usually children acidotic
10. Genetic counselling
    a. Acrodermatitis enteropathic – AR
    b. Acquired – zinc replacement

Question 31

Preauricular sinuses and pits

Answer 31

a. May be due to imperfect fusion of the first and second brachial arches
b. Associated with EYA-1 gene mutation (branchio-otorenal dysplasia 1 syndrome)
i. Autosomal dominant
ii. External ear malformations
iii. Branchial fistulas
iv. Hearing loss
v. Renal abnormalities

Question 32

Redundant skin

Answer 32

a. Redundant skin over the posterior part of neck common in
i. Turner
ii. Noonan
iii. T21
iv. Klippel-Feil syndromes

Question 33

Accessory tragus

Answer 33

a. Tragus arises from first branchial arch
b. Rest of pinna arises from the second branchial arch
c. Accessory trachi  chromosomal 1st branchial arch syndromes
d. Associated with Goldenhar syndrome (oculo-auriculo-vertebral syndrome)

Question 34

Branchial cleft and thyroglossal cyst

Answer 34

a. Can occur along course of 1st/2nd/ 4d and 4th branchial clefts
b. Thyroglossal cysts
i. Vertical motion with tongue protrusion + swallowing
ii. Often appears after an URTI

Question 35

Supernumery nipples

Answer 35

a. May be associated with renal/urinary tract anomalies

Question 36

Cutis aplasia

Answer 36

a. Developmental absence of the skin
b. Variable appearance depending on time of formation
c. Early lesions may heal over -> atrophic, fibrotic scars
d. Often surrounded by collar of hair

e. Associated syndromes
i. Opitz
ii. Dams-Oliver
iii. T13-15
iv. Chromsome 16-18 defects

f. Associated congenital anomalies
i. Meningomyelocele
ii. Gastroschisis
iii. Omphalocele
iv. Spinal dysraphism

g. Complications = infections, haemorrhage, meningitis

Question 37

Focal dermal hypoplasia

Answer 37

= Goltz syndrome

a. Rare congenital disorder
b. X-linked dominant
c. Mutation in PORCN gene
d. Soft tan papillomas, linear atrophic lesions, reticulated hypopigmentation, telangiectasias, congenital absence of skin etc

Question 38

Ectodermal dysplasias

Answer 38

• Defects of 2 or more of = teeth, skin, appendage structures
• > 150 types identified

• Anhidrotic ectodermal dysplasia
o Triad of hypohidrosis, anomalous dentition, hypotrichosis
o X linked form the most common
o Typical facies = frontal bossing, malar hypoplasia, flattened nasal bridge, thick, everted lips

• Hidrotic ectodermal dysplasia:
o AD inheritance
o Dystrophic/ hypoplastic nails, spares hair, hyperkeratosis of palms and soles

Question 39

Vascular malformation vs tumour

Answer 39

• Vascular malformation = developmental disorder of blood vessel formation, slowly enlarge
o Capillary malformations
 Nevus simplex (macular stain)
 Port-wine stain
o Lymphatic malformation
 Macrocystic lymphatic malformation (cystic hygroma)
 Microcystic lymphatic malformation (Lymphangioma circumscriptum)
o Venous malformation
o AV malformation

•	Tumours = endothelial cell hyperplasia and proliferation 
o	Infantile haemangioma 
o	Pyogenic granuloma
o	Kaposiform haemangioendothelioma
o	Tufted angiomas

Question 40

Infantile haemangioma - bg, sx, natural hx

Answer 40

1. Key points
   a. Characterised by growth phase and involution phase – contrasting vascular malformations (derived from capillaries, arteries, veins, lymphatics or combination) which grow with child and do not regress
   b. Most common tumour of infancy – approx 4-5%
   c. Familial transmission in AD fashion has been reported
2. Clinical presentation
   a. Majority are not clinically evident at birth but become apparent within the first few days to months of life
   i. 1/3 present at birth, rest manifest by 6 months of age
   b. Early lesions subtle or may resemble port-wine stain
   c. Majority solitary – multiple in 20%
   d. Most common head and neck
   e. Range in size
   f. Blanch with pressure
   g. Classification
   i. Superficial = bright red papule, nodule or plaque raised above normal skin; called ‘capillary’ or ‘strawberry’ haemangioma
   ii. Deep = raised, skin-coloured nodule which often has a bluish hue with or without a central telangiectastic patch; also called cavernous haemangiomas
   iii. Combined = both superficial and deep components
3. Natural history
   a. 6-9 months = proliferation; slow proliferation can continue for first 6-9 months (uncommon after first year); largest increase in size during the first 5 months
   b. >1 year = spontaneous involution phase
   c. Complete involution = 10%/year – approximately 50% involuted by age 5 years
   d. Minority of cases fail to proliferate beyond telangiectastic patch associated with premonitory stage

Question 41

PHACE syndrome

Answer 41

1. Neurovascular syndrome defined by large, segmental haemangioma, usually on face or head
2. Associated with one or more congenital abnormality (P = posterior fossa brain malformation, H = haemangioma, A = arterial anomaly, C = cardiac and coarctation, E = eye and endocrine, S = sternal clef, supra-umbilical raphae)

Question 42

Infantile haemangioma - ix, cx

Answer 42

7. Investigations
   a. >5 haemangiomas = abdominal USS and clinical monitoring for hepatic haemangiomas
   b. Lumbosacral = MRI to investigate for spinal dysraphism
   c. PHACE = evaluation for opthal, cardiac and neurological disease (MRI, echo)
   i. If on upper part of face: brain and eye more likely relevant
   ii. Lower part of face: heart and great vessel abnormality more likely
   iii. Segmental haemangioma 1/3 have an association
8. Complications
   a. Ulceration = frequent in trauma or pressure prone areas
   b. Bleeding
   c. Permanent disfigurement
   d. Kasabach-Merritt phenomenon = severe thrombocytopaenia and/or coagulopathy from platelet trapping in vascular tumour
   e. Compromise organ function

Question 43

Kasabach-Merritt phenomenen

Answer 43

Severe thrombocytopaenia and/or coagulopathy from platelet trapping in vascular tumour

Question 44

Infantile haemangioma - areas of concern

Answer 44

Facial, large segmental -> PHACE syndrome

Periorbital and retrobulbar
•	Ocular axis occlusion
•	Astigmatism
•	Amblyopia
•	Tear-duct occlusion

Segmental “beard area,” central neck
• Airway hemangioma – develop symptoms between 6-12 weeks of age (when haemangioma proliferation is rapid)
• Found in 2/3
• Untreated present at 6-12 weeks of age with stridor, cough, feeding difficulties

Segmental overlying lumbosacral spine
• Tethered spinal cord
• Genitourinary anomalies

Multiple hemangiomas
• Visceral involvement (especially liver, gastrointestinal tract)
- Hepatic haemangiomas
• Usually asymptomatic
• Can have large vessel shunts resulting in CHF

Question 45

Infantile haemangioma - rx

Answer 45

a. Indications for treatment
i. Very large, rapidly growing
ii. Lesion in periorbital region
iii. Lesion in airway, liver or GIT
iv. Lesions associated with ulceration or scarring/disfigurement

b. Treatment options

i. Uncomplicated
1. Observation
2. Beta blockers (hypoglycaemia, sleep disturbance, bradycardia, bronchospasm)
3. Local: topical timolol (0.5%)
i. Should NOT replace systemic therapy in patients with clear indication for therapy
ii. Small, flat facial haemangioma
b. Topical and intralesional corticosteroids

ii. Complicated
1. Propranolol
2. Systemic corticosteroids – rare
3. Surgical therapies
4. Laser – penetrates <1mm to the skin (only useful if very early, useful for ‘leftover’ telangiectasia)

Question 46

Propranolol for infantile haemangiomas

Answer 46

1. Dose = 1-3mg/kg/day (three doses) – start at 1 mg/kg/day in divided doses and double after 2/52
2. Action = non-selective B antagonist – negative inotropic and chronotropic effect
3. Efficacy = 85% response rate
4. Adverse effects
   h. Hypotension/bradycardia peaks 2 hours post dose
   b. Pulmonary = bronchoconstriction, wheeze
   c. Hypoglycaemia (blocks GNG)
   d. Sleep disturbance
   e. Mottled extremities
   f. Diarrhoea (most common)
   g. Hyperkalaemia
5. Contraindications
   a. Cardiogenic shock, hypotension + CCF
   b. Sinus bradycardia, first degree heart block
   c. Bronchial asthma
   d. Hypersensitivity
   e. Preterm infant with age <5 weeks
6. Recommend before use = history, ECG, family history
7. Starting
   a. Up titrate and check BP/HR 2 hours post change in dose – do not need admission unless premature
   b. Education regarding signs of hypoglycaemia – all masked EXCEPT sweating
   c. Only need check once then safe
   d. Only need inpatient initiation <8weeks age
8. Those with PHACE syndrome
   a. Risk of stroke given often have cervical stenosis and arteriopathy (coarctation) as part of syndrome – hypotension from BB resulting in ischemia
   b. Recommend MRI angiography prior to treatment
   c. Discuss with Cardiology on case by case basis

Question 47

Kaposiform haemangioendothelioma (KHE) + Tufted Haemangiomas

Answer 47

a. Rare and potentially life-threatening vascular tumour
b. Present as red to purple firm plaque on lateral neck, axilla, trunk or extremities
c. Visceral tumours can also occur
d. Lesions occasionally

e. Key complication = Kasabach-Merritt phenomenon
i. Key features
1. Rapidly enlarging KHE
2. Thrombocytopaenia
3. MAHA
4. Acute or chronic consumptive coagulopathy
ii. Treatment
1. Surgical excision
2. Pharmacological = steroids, vincristine, antiplatelet, anti-fibrinolytic

Question 48

Spider angioma

Answer 48

a. Pressure over the central vessel cases blanching
b. Associated with conditions with elevated estrogen
c. Occur in 15% of normal preschool aged children

Question 49

Syndromes with angiomas

Answer 49

1. Hereditary haemorrhagic telangiectasia (Osler Weber Rendu)
   a. AD disorder, HHT1 or 2
   b. Clinical manifestations: epistaxis, skin and mucous membrane lesions (red-purple macules with spider like projections)
   c. Complications: massive haemorrhage/anaemia
2. 15-20% with AVMs present with stroke due to embolic abscesses
   d. Treatment = supportive
3. Hereditary benign telangiectasia
   a. AD trait
   b. Skin telangiectasias
4. Ataxia telangiectasia
   a. Mutation in ATM gene
   b. Clinical manifestations
   i. Telangiectasias
   ii. Café-aut-lait spots
   iii. Premature greying of hair
   iv. Progressive cerebellar ataxia, neurologic deterioration
   v. Sinopulmonary infections (variable immune deficiency)
   vi. Malignancy: 1% / year after 10 years of age (mostly lymphomas and leukaemias)
5. Fabry disease
   a. Inborn error of glycolipid metabolism
   b. Second most common lysosomal storage disorder
   c. X linked
   e. Clinical manifestations
   i. Severe neuropathic/ limb pain
   ii. Telangiectasias and angikeratomas
   iii. Renal disease
   iv. Progressive cardiac/ cerebral involvement
   f. Investigations – enzyme levels in leukocytes
   g. Treatment – enzyme replacement

Question 50

Naevus flammeus - bg, sx, natural history

Answer 50

= port wine stain = capillary malformation

1. Key points
   a. Low-flow vascular malformation of dermal capillaries + post-capillary venules
   b. Usually isolated cutaneous anomalies but may be associated with other abnormalities
2. Clinical manifestations
   a. Variably blanchable pink to red patches
   b. Unilateral or segmental distribution that respects midline
   c. Face – common location (particularly follow distribution of trigeminal nerve)
   d. Comparison to capillary haemangioma
   i. Flatter, darker (not palpable)
   ii. Does not blanch with pressure
   iii. Typically unilateral/ segmental (often ends on midline)
   e. Can involve mucosal surface
3. Natural history
   a. Present at birth – blanchable pink to red patches
   b. Increases in size in proportion to child’s growth – do NOT regress
   c. Become thicker and darker in color, may become nodular

Question 51

Naevus flammeus - associations, complications

Answer 51

a. Glaucoma
i. 18% periocular capillary malformation especially if involves upper and lower eyelids
ii. 50% if Sturge Weber syndrome
b. Occult spinal dysraphism = controversial
c. Soft tissue / bone overgrowth = e.g. maxillary or gingival hyperplasia if on face
d. Thickening and nodularity = 65% lesions especially on face

e. Syndromes
i. Sturge Weber (triad – port wine V1/2, leptomeningeal angiomatosis, ocular)
ii. Kippel-Trenaunay (port wine limb, venous/lymphatic malformation, soft tissue and bone hypertrophy)
iii. Parkes-Weber syndrome (port wine limb, soft tissue/bone hypertrophy, multiple AV shunts with CCF)

Question 52

Naevus flammeus - ddx

Answer 52

a. Nevus simplex
i. Salmon patch or stork bite; common birthmark occurring in 80% of newborns
ii. Similar in appearance, but has more indistinct border and usually in midline
iii. Common locations – glabella (above/between eyebrows), upper eyelid, nape of neck
iv. Fade spontaneously over time

b. Infantile haemangioma
i. 1/3 of cases infantile haemangioma present at birth as macular telangiectatic patch similar to capillary malformation; often have surrounding pallor representing vasoconstriction
ii. Haemangiomas quickly develop small vascular blebs and become raised

c. AV malformation
i. May present as macular vascular patches
ii. Often warm to touch and may have thrill on palpation
iii. AV malformations progressively raise and develop deep component

Question 53

Naevus flammeus - ix, rx

Answer 53

5. Investigations
   a. Not routine
   b. MRI-B if Sturge-Weber suspected
   c. USS to identify venous varicosities in children with Klippel-Trenaunay syndrome
6. Management
   a. Ophthalmological examination to rule out glaucoma in any V1/V2 capillary haemangioma
   b. Consider investigations for associated syndromes
   c. Pulsed dye laser therapy – standard of care, lightens port wine stain without causing scarring
   i. Early treatment is preferable – smaller, easily held, better response -> EARLY REFERRAL

Question 54

Venous malformation

Answer 54

• Vein-only malformation and combination malformations
• Most venous malformations are sporadic
• 40% of sporadic venous malformations caused by TIE2 mutation
• Treatment = surgical excision

Question 55

Cutaneous marmorata telangiectasia congenita

Answer 55

• Benign vascular anomaly that represents dilatation of superficial capillaries and veins
• Apparent at birth
• Results in reticulated red or purple hue that resembles physiologic cutis maromarata
• Associations
o CM
o Adams-Oliver syndrome
o PDA

Question 56

Blue rubber bleb naevus syndrome

Answer 56

• Venous malformations of the skin, mucous membrane and GIT

* Blue-purple and rubbery in consistency

Question 57

Arterio-venous malformation

Answer 57

• Direct connection of artery to a vein and bypasses capillary bed
• AVM of skin are rare
• Skin changes are often noted at birth but tend to be subtle
• Some AVMs are progressing and can lead to morbidity and early mortality

Question 58

Lymphangioleiomyomatosis

Answer 58

a. Proliferation of lymphatic endothelial cells and smooth muscle
b. May be mistaken for asthma
c. Occurs in young women
d. Associated with mutations in TSC2 in 1/3
e. Treatment = Sirolimus

Question 59

Lymphoedema

Answer 59

a. Localised swelling caused by impaired lymphatic flow
b. Congenital
i. Turner syndrome
ii. Noonan syndrome
iii. Milroy disease
iv. Lymphedema praecox (Meige disease) progressive lower extremity edema
v. Hypotrichosis-lymphedema-telangiectasia syndrome
c. Acquired
i. Filariasis

Question 60

Naevus - definition

Answer 60

Collection of well differentiated skin cells -> can be vascular/ melanocytic

Question 61

Melanocytic naevi - general

Answer 61

1. Congenital melanocytic naevi
   a. Present at birth, occurs in 1% of newborn infants
   b. Classified by size (large >20cm, small <1.5cm)
   c. Appearance
   i. Raised lesions, varying shades of brown to black with irregular margins and dark hairs
   ii. Develop hair
   iii. Grow in proportion to child – tend to occur on lower trunk, upper back, shoulders, chest
   d. Histology = naevus cells in lower reticular dermis
   e. RISKS
   i. 5% undergo malignant change to melanoma
   ii. Risk proportional to size
2. Acquired melanocytic naevi (freckle!)
   a. Benign cluster of melanocytic naevus cells that arise from proliferation of melanocytes at the epidermal junction
   c. Increased number correlates with risk of melanoma
   d. Can be classified by histological junction (junctional, compound, dermal)
3. Atypical melanocytic naevi
   a. Are basically high risk melanocytic naevi
   b. Can be sporadic/ associated with AD familial melanoma
   c. Large, irregular margins, variegated colour, elevation
   d. Histology: atypical intraeperidermal melanocytes +/- angiogenesis
   e. <0.1% risk of developing melanoma
4. Melanoma
   a. Accounts for 1-3% of all paediatric malignancies (2% of melanoma in children)
   b. Risk factors
   i. Atypical mole-melanoma syndrome
   ii. Xeroderma pigmentosum
   iii. Acquired melanocytic naevi, atypical naevi

Question 62

Naevus of Ota and Ito

Answer 62

• Nevus of Ota
o Permanent patch of confluent black/ blue/ brown macules
o Can enlarge and darken with time
o Occurs in region of the trigeminal nerve
o Looks speckled compared to Mongolian spot
o Due to mid-dermal melanocytosis
o Can arise in second decade of life
o May be decreased by laser therapy

• Naevus of Ito
o Similar to above but more diffuse in distribution

Question 63

Normal pigmentation

Answer 63

a. Melanocytes migrate from the neural crest to the dermal-epidermal junction
b. Melanocytes make melanosomes which contain pigment
c. Melanosomes transfer pigment to surrounding keratinocytes

Question 64

Hyperpigmented lesions - general

Answer 64

a. Freckles = increased melanin pigment in epidermal basal cells – have more dendritic processes than the melanocytes of surrounding skin

b. Lentigines = small round dark brown macules – UNRELATED to sun exposure
i. Increased number of melanocytes and dense epidermal deposits of melanin (no nests of melanocytes which are present in naevi)
ii. Associated syndromes
1. LAMB syndrome
2. LEOPARD syndrome
3. Peutz Jeghers

c. Café au lait spots
i. Uniformly pigmented, sharply demarcated macular lesions
ii. Increased melanin and numbers of melanin WITHOUT clubbed rete ridges present in lentigines
iii. 1-3 are normal
iv. Associated syndromes
1. Neurofibromatosis
3. Turner’s syndrome
4. Russell-Silver syndrome
5. McCune-Albright syndrome
6. Fanconi anaemia
7. Bloom syndrome
8. Cowden syndrome
9. Ataxia-Telangictasia
10. MEN-1, MEN2B

Question 65

Albinism spectrum - general

Answer 65

= partial/complete failure in melanin production

i. Oculocutaneous albinism
1. 7 different types
2. Inherited in AR pattern
3. Disorder of melanin biosynthesis – tyrosinase, tyrosinase-related protein, specific transport proteins found in melanosomes
4. Absent or reduced pigmentation of hair, skin and eyes

ii. Ocular albinism
1. Hypopigmentation primarily limited to the eyes – LESS common than oculocutaneous albinism

iii. Hermansky public syndrome
1. Oculocutaneous albinism, ceroid accumulation in lysosomes and prolonged bleeding time

iv. Chediak Higashi syndrome
1. Problem with lysosome related organelles  hypopigmentation, prolonged bleeding time, recurrent infections

Question 66

Vitiligo

Answer 66

i. Destruction of melanocytes – autoimmune/ genetic basis
ii. Can be generalized or segmental
iii. Treatment – may trial topical steroid/ tacrolimus/ pimecrolimus

Question 67

Waardenburg syndrome

Answer 67

White forelock + deafness

1. AD
2. Localized areas of depigmented skin and hair
3. Four types – most characteristic is white forelock + deafness (type1)
4. Patchy depigmentation of the hair and skin
5. Non-cutaneous features
   a. Pigmentary abnormalities of the iris (heterochromia irides)
   b. Broad nasal root
   c. Congenital deafness
   d. Cleft palate + NTD

Question 68

Hypomelanosis of Ito

Answer 68

/Blaschkoid hypomelanosis

1. Thought to be due to chromosomal mosaicism and translocation
2. AD inheritance
3. Rare
4. Congenital skin disorder
5. Clinical features
   a. Hypopigmentation in whorls – small 0.5-1cm hypopigmented/white macules form reticulated patches along lines of Blaschko, Wood lamp enhances
   b. Dysmorphism – microcephaly 25%, hypotonia, cleft palate, hemihypertrophy, lamb/hand/foot anomalies, teeth abnormalities, hair anomalies, face and/or skull anomalies
   c. Seizures 40%
   d. Mental retardation 70%
   e. Ophthalmologic anomalies 25%
   f. Heterotopias

Question 69

Bullous disorders - gen bg, types

Answer 69

1. Types of blisters
   a. Epidermal blisters: thin walled, flaccid, easily ruptured
   b. Subepidermal blisters: thick walled and more durable
2. Aetiology
   a. Acrodermatitis enteropathic (zinc deficiency)
   b. Bullous impetigo
   c. Bullous pemphigoid
   d. Epidermolysis bullosa
   e. Pemphigus vulgaris
   f. Dermatitis herpetiformis
   g. Drug reactions -erythema multiforme, SJS/ TENS (see above)
   h. Infections – HSV/ VZV/ staph scalded skin

Question 70

Epidermolysis bullosa - general

Answer 70

1. Classification
   a. Simplex = intraepidermal blisters, keratin mutations (mostly AD)
   b. Junctional = intra-lamina, integrin/ laminin mutations (AR)
   c. Dystrophic = subepidermal lamina, collagen mutations (AR/ AD)
2. Clinical manifestations
   a. Skin features
   i. Most present with bullae at birth
   ii. Range from severe with mucosal involvement + early death  onset in childhood
   iii. Fragile skin, blistering with minor trauma
   b. Associated features
   i. Ectodermal problems: hair/ tooth / nails
   c. Scarring prominent
3. Treatment
   a. Prevent trauma
   b. Careful wound care
   c. Pain management
4. Prognosis
   a. Simplex = very variable, can be widespread/ localized
   b. Junctional = most patients die within first 3 years of life,
   c. Dystrophic = tends to be severe

Question 71

Pemphigus vulgaris and foliaceous

Answer 71

Pemphigus Vulgaris

1. Pathogenesis
   a. Circulating antibodies to desmoglein III
   b. Suprabasal cleaving, igG +ve
2. Clinical manifestations
   a. Painful oral ulcers
   b. Large bullae on face, trunk, pressure points
   c. Nikolsky sign +ve
   d. Can have neonatal form due to maternal IgG
3. Treatment
   a. Systemic immunosuppression – steroids, azathioprine, cyclophosphamide, MTX

Pemphigus Foliaceous
• Due to circulating antibodies to desmoglein I  cleavage high I the epidermis
• Clinical manifestations
o Superficial blisters, most common scalp, face, neck and trunk
o Can look like dermatitis/ psoriasis or impetigo
• Treatment = topical steroids

Question 72

Bullous pemphigoid

Answer 72

• Antibodies to upper lamina lucida  subepidermal blisters
• Clinical manifestations
o Blisters usually occur on erythematous/ eczematous/ urticarial base
o Usually on flexures (oral lesions uncommon)
• IF = IgG and C3 on basement membrane
• Uncommon in children
• Usually responds to topical therapy

Question 73

Dermatitis herpetiform

Answer 73

• Associated with coeliac disease, HLADQ2 (90%), HLA DQ8
• Clinical manifestations
o Symmetric, tense erythematous pruritic papules and vesicles
o Knees, elbows, buttocks and scalp (mucous membranes SPARED)
• Granular IgA in dermal papillary tips

Question 74

Erythema multiforme - bg

Answer 74

1. Key points
   a. < 1% annually
   b. Most common in 20-40 year age group
   c. Acute immune-mediated condition characterised by presence of target-like lesions
2. Aetiology
   a. Infections account for 90% of cases
   i. HSV is classic
   ii. Mycoplasma – more classic for SJS/TEN
   b. Other things: medications, malignancy, autoimmune disease, immunizations, radiation, sarcoidosis
3. Pathogenesis (mostly studied in setting of HSV)
   a. Expression of foreign pathogen in skin (eg HSV genes)
   b. Recruitment of CD 4+ Th1 cells that produce interferon gamma
   c. Inflammatory cascade  lysis of keratinocytes, recruitment of autoreactive T cells  epidermal damage and inflammatory infiltrate

Question 75

Erythema multiforme - sx, rx

Answer 75

4. Clinical features
   a. Target lesions – MUST have a lesion/ erosion in centre
   i. Mainly on extensor surfaces, centripetal manner
   ii. Worse at sites of trauma and sunburn
   iii. Usually symmetrical
   iv. Most common on upper limb
   b. Erosions/ bullae may oral / genital/ ocular
   i. If mucosal SJS/TEN should be considered
   c. Systemic symptoms are uncommon
   d. Usually appear over 3-5 days, resolve over 2 weeks
5. Differentials
   a. Urticaria
   b. SJS/ TENS
   c. Fixed drug eruption
   d. Pemphigoid
6. Treatment
   a. Treat underlying cause
   b. Mild disease: topical corticosteroids + oral antihistamines
   c. Oral mucosa involvement – systemic glucocorticoids
   d. Ophthal review if ocular symptoms
   e. If severe/ recurrent can trial azathioprine, mycophenolate or dapsone

Question 76

Allergic contact dermatitis - general

Answer 76

a. Pathogenesis
i. Substance elicits delayed hypersensitivity (type IV) reaction
ii. Ag exposed to skin, conjugated with cutaneous protein  presented to Langerhans cells  t cells

b. Triggers
i. Poison ivy (oleoresin), oak
ii. Nickel, formaldehyde, rubber
iii. Topical steroids, topical antibiotics

c. Clinical manifestations
i. Intensely pruritic rash
ii. Papular erythematous dermatitis with indistinct margins
iii. Can ooze
iv. Can affect remote sites from transfer of allergens by hands
v. Poison ivy typically linear lesions representing contact with leaves

d. Treatment
i. Avoidance of irritant or allergen
ii. Topical corticosteroids = if localised
iii. Topical calcineurin inhibitors
1. Chronic, localised
2. Localised resistant to topical corticosteroids
3. Localised involving face or intertriginous area
iv. Treatment of secondary bacterial infection
v. Systemic corticosteroids
1. Oral corticoids are the first line if involving >20% of the body surface area, OR for acute ACD involving the face, hands, feet or genitalia if quick relief required
vi. Systemic antihistamines may help itch

Question 77

Irritant contact dermatitis - general

Answer 77

a. Pathogenesis
i. Exposure to substances that cause physical, mechanical or chemical irritation of skin

b. Aetiology
i. Soapy water, cleansers, rubbing alcohol
ii. Bleach, strong acids, alkalis can produce severe dermatitis after 1 exposure

c. Clinical manifestations
i. Erythema, chapped skin & fissuring
ii. Pruritis can range from mild to extreme

d. Treatment
i. Decrease exposure to soap, increase use of emollients
ii. Corticosteroid ointments
iii. Gloves
iv. Systemic corticosteroids ARE NOT USEFUL

Question 78

Nummular eczema - general

Answer 78

• Coin-shaped, severely pruritic, eczematous plaques – commonly involve extensor surfaces of extremities, buttocks, and shoulders
• Aetiology unclear
• Flares sporadic but may be precipitated by similar triggers as atopic eczema
• Treatment as for atopic eczema

Question 79

Pityriasis alba - general

Answer 79

• Hypopigmented, ill-defined, round or oval patches
• May be mildly erythematous and finely scaly
• Most pronounced on dark skin
• Itching minimal or absent
• Cause unknown

Question 80

Lichen simplex chronicus - general

Answer 80

• Secondary skin disorder
• Results from excessive scratching
• Characterised by a chronic pruritic, eczematous, circumscribed plaque that is usually lichenified and hyperpigmented

Question 81

Acute palmoplantar eczema - general

Answer 81

• Recurrent, occasionally seasonal, blistering disorder of hands and feet
• Occurs in all age groups but is uncommon in infancy
• Unknown pathogenesis

Question 82

Seborrheic dermatitis - general

Answer 82

1. Key points
   a. Characterized by erythema and scale, often pruritic
   b. Pathogenesis not understood
   c. Note – in infants > 4 months, much more likely to have eczema than seborrheic dermatitis
2. Pathogenesis
   a. Not understood fully: chronic inflammatory disease
   b. Pityrosporum ovale yeast linked to excessive seborrheic dermatitis
   c. More common in infancy and adolescence therefore likely related to hormonal influences
3. Clinical manifestations
   a. Affects
   i. Lateral sides of nose
   ii. Eyebrows and glabella
   iii. Scalp (Cradle cap)
   iv. Trunk
   v. Flexural areas
   b. Looks like: scale and crust +/- pruritic
4. Treatment
   a. Dandruff (seborrheic dermatitis of scalp)
   i. Daily shampoo with medicated shampoo (sulphur and salicylic acid)
   ii. Tea tree oil is natural remedy
   iii. Wet compresses prior to application
   iv. +/- topical antifungals
   b. Non scalp seborrheic dermatitis
   i. Topical corticosteroids
   ii. Antifungals (ketoconazole) or combination of the two
   iii. In severe disease, tacrolimus/ pimecrolimus may have a role

Question 83

Photosensitivity - general

Answer 83

Definition = qualitatively or quantitatively abnormal cutaneous reaction to sunlight or artificial light due to UV radiation

1. Cutaneous reactions to sunlight
   a. Photoallergic drug eruptions (e.g. tetracyclines)
   b. Phototoxic drug eruptions
   c. Genetic disorders with photosensitivity
   i. Xeroderma pigmentosum
   ii. Bloom syndrome
   d. Inborn errors of metabolism
   i. Porphyrias, protoporphyria
   e. Infectious diseases associated with photosensitivity:
   i. Recurrent herpes simplex infection
   ii. Viral exanthems (accentuated photodistribution; e.g., varicella)
   f. Skin disease exacerbated or precipitated by light
   i. Lichen planus
   iii. Lupus erythematosus including neonatal
   iv. Dermatomyositis
   v. Psoriasis
   vi. Erythema multiforme
   vii. Atopic dermatitis
   g. Deficient protection because of a lack of pigment:
   i. Vitiligo
   ii. Oculocutaneous albinism
   iii. Phenylketonuria
2. Porphyrias
   a. Acquired or inborn disorders due to abnormalities of specific mutations in the haem biosynthetic pathway
   b. Childhood photosensitivity is a common feature
   c. Results from excess porphyrins in the skin; UV radiation  ROI  skin damage
3. Xeroderma pigmentosum
   a. Rare AR disorder
   b. Results from defect in nucleotide excision repair
   c. Clinical manifestations
   i. Skin changes = erythema, scaling, bullae, crusting, freckles, telangiectasia, keratosis
   ii. SCC and malignant melanoma
   iii. Neurological abnormalities = cognitive deterioration, sensorineural deafness (20%)
   d. Treatment
   i. Total protection from sunlight
   ii. Early detection and removal of malignancies
   e. Prognosis
   i. Shortened lifespan

Question 84

Psoriasis - general

Answer 84

1. Key points
   a. Characterised by proliferation + abnormal differentiation of keratinocytes due to primary T cell abnormality
2. Clinical manifestations
   a. Usually presents in first 2 decades of life
   b. Erythematous papules that coalesce to form plaques – sharply demarcated, irregular borders
   c. Silvery or yellow white scale
   d. Nail changes: Pitting, hyperkeratosis, Onycholysis, Ridging, Dactylitis
3. Treatment
   a. First line = topical therapy – steroids (vitamin D analog calcipotriene + topical retinoid, tar and anthralin may be useful)
   b. Second line = phototherapy
   c. Third line = systemic therapy – TX, oral retinoids, cyclosporine
   d. Fourth line = biologics etanercept, infliximab, adalimumab

Question 85

Pityriasis rosea - general

Answer 85

a. Thought to be a viral rash – HHV7/8
b. Starts with herald patch (solitary round/ oval lesion)
i. Usually near proximal joint
ii. Larger than other patches
c. Systemic eruption 5-10 days later
i. Symmetrical proximal
ii. Christmas tree pattern
iii. Free edge of scale internally
d. Usually lasts 3 to 6 weeks
e. DDx = drug eruption, secondary syphilis, guttate psoriasis, discoid eczema, pityriasis lichenoides
f. No treatment required – may have post-inflammatory hypo/hyperpigmentation
i. Topical steroids and/or UVB

Question 86

Disorders of keratinisation

Answer 86

• Mendelian disorders of cornification (ichthyoses) are a group of inherited conditions characterised by
o Clinical = scaling
o Histopathological = hyperkeratosis

Eg icthyosis vulgaris, X-linked icthyosis

Question 87

Icthyosis vulgaris - general

Answer 87

a. Most common disorder of keratinization
b. Genetics
i. AD
ii. Mutation in filaggrin

c. Clinical manifestations
i. Onset in the first year of life
ii. Usually slight roughening of the skin, scaling on extensor aspects of extremities
iii. Flexural surfaces spared
iv. Keratosis pilaris
v. Hyperkeratosis on palms and soles

d. Treatment = moisturizer, salicyclic acid

Question 88

X-linked icthyosis - general

Answer 88

a. Genetics
i. Steroid sulfatase deficiency
ii. X linked

b. Clinical manifestations
i. Skin peeling typically from 3-6 months of life
ii. Scaling
iii. Gradually worsens in severity and extent

c. Contiguous gene deletion syndromes
i. Kallman syndrome = hypogonadotrophic hypogonadism + anosmia
ii. X-linked chondroplasia punctate
iii. Short stature
iv. Ocular albinism

d. Treatment
i. Emollient and urea-containing lubricant
ii. Glycolic or lactic acid

Question 89

Harlequin icthyosis - general

Answer 89

a. Mutation in ACA12 gene, autosomal recessive
b. Presents at birth with markedly thickened, ridged and cracked skin – disfigures facial features and constricts the digits, nail and hair absent
c. Respiratory difficulty, suck poorly and develop severe infections
d. Previously uniformly fatal
e. With oral retinoids 80% survive beyond infancy

Question 90

Mastocytosis - general

Answer 90

ie mast cells

1. Natural history
   a. Can occur any time from birth -> adulthood
   b. 65% present in childhood (most of these by 2 years)
2. Classification
   a. Cutaneous
   i. Urticaria pigmentosa (most common)
   ii. Diffuse cutaneous mastocytosis
   iii. Mastocytoma of the skin
   b. Systemic
   i. Without leukemic mast cell disease
   ii. With leukaemic mast cell disease
   c. Mast cell leukaemia
   d. Mast cell sarcoma
3. Clinical manifestations
   a. Urticaria pigmentosa most common form
   i. Brown/ red macules of varying size, usually on the trunk
   ii. Itch and blisters prominent
   iii. Dermatographism +ve (develop welts or a localized hive-like reaction when they scratch their skin)
   iv. Biopsy shows accumulation of mast cells
   v. If this is isolated feature, usually resolves by adolescence
   b. Diffuse cutaneous mastocytosis
   i. Seen exclusively in infants
   ii. Skin red/brown discolouration and thickened peau d’orange appearance
   iii. Increased risk of flushing, hypotension, shock and death
   iv. Extracutaneous disease more common
   c. Mastocytoma
   i. Brown nodules – can be solitary/ multiple
   ii. Trauma to nodule  flushing and hypotension
   iii. Histology: sheets of mast cells
   d. Extra cutaneous manifestations (uncommon in children)
   i. Systemic: pruritis, flushing, bone pain, headache
   ii. GIT: abdominal pain, bleeding
   iii. CVS: hypotension and shock
   iv. Hepatosplenomegaly, normocytic anaemia
   e. Adverse reactions to mast cell degranulating agents seen: ETOH, NSAIDS, thiamine, narcotic
4. Investigations
   a. Biopsy
   b. Elevated tryptase, histamine
5. Treatment
   a. Avoid triggers
   b. Antihistamines
   c. Paediatric onset is usually benign with most cases resolving by adolescence

Question 91

Lichen sclerosis

Answer 91

a. Shiny, indurated, ivory covered papules with violaceous halo
b. Often occurs in the vulvar, perianal and perineal skin
c. Histology = follicular plugging, degeneration of basal cells, band like dermal lymphocytic infiltrate
d. Treatment = steroids may relieve pruritus. Monitor for development of SCC

Question 92

Erythema nodosum - general

Answer 92

a. Aetiology
i. Infection
1. Viral = EBV, HPV, mumps
2. GAS – most common
3. Fungal infection
4. Cat scratch
5. Yersinia
ii. Sarcoidosis
iii. IBD
iv. Medications = cephalosporins, penicillins, macrolides

b. Clinical manifestations
i. Tender red nodules with indistinct borders on extensor surfaces of the arms and legs
ii. May resolve in 1-6 weeks

c. Treatment = supportive

Question 93

Panniculitis - general

Answer 93

a. Inflammation of subcutaneous fatty tissue
b. May occur post steroid use
c. Mixed infiltrate of lymphocytes/ histiocytes and neutrophils
d. Treatment = supportive
e. Can occur in alpha 1 antitrypsin deficiency, post steroid use, pancreatitis , in exposure to cold

Question 94

Chillblains/pernio - general

Answer 94

a. Due to vasospasm of arterioles due to damp cold exposure  hypoxemia
b. Associated with lupus, anorexia, cryoglobulins
c. Treatment = prevention/nifedipine if severe

Question 95

Lipodystrophy - general

Answer 95

Dermnet: Lipodystrophy (also called lipoatrophy) usually infers loss of fat. The fat layer is subcutaneous (it lies underneath the skin). Loss of subcutaneous fat leads to an increased definition of the structures underneath (muscle and bone) and presents as one or more depressions in the skin. If all the underlying structures are affected, it is called panatrophy.

Lipodystrophy may be congenital (the tendency to lose fat is present at birth) or acquired (the loss of fat occurs later in life). Lipodystrophy can affect all of the body (generalised lipodystrophy) or just parts of the body (partial lipodystrophy).

a. Partial lipodystrophy can be familial/ acquired
b. Generalized lipodystrophy
i. Congenital forms = marked lipodystrophy from birth/ early infancy
ii. Acquired = most common in juvenile dermatomyositis, may ne associated panniculitis

Question 96

Types of sweat glands

Answer 96

a. Eccrine glands = all over skin surface, main form of cooling  secrete odourlesss aqueous sweat
b. Apocrine sweat glands = axilla, anogenital, mammary glands  secrete viscous fluid that is altered by microorganisms to produce body odour

Question 97

Sweat gland disorders

Answer 97

2. Anhidrosis
   a. Aetiology
   i. Neuropathic
3. Disturbance in neural pathway from brain  peripheral efferent fibres that activate sweating
   a. Pontine/ medullary lesions: ipsilateral face/ neck, ipsilateral/ contralateral for face and body
   b. Segmental neuropathies
   c. Autonomic disordrs
   ii. Anticholinergics (atropine/ scopolamine) – may paralyze the sweat glands
   iii. Other causes – Addison disease, uraemia, lead poisoning, DI, hyperthyroidism, Fabry disease
   b. Complication = hyperthermia
4. Hyperhydrosis
   a. Excessive sweating
   b. May be treated with 20% aluminium chloride + anhydrous ethanol, iontophoresis, botox, oral anticholinergics, sympathectomy
5. Milaria
   a. Caused by retention of sweat in occluded eccrine sweat ducts
   b. Milaria crystalline = asymptomatic, non inflammatory pinpoint clear vesicles
   c. Milaria rubra = erythematous minute papulovesicles
   d. Milaria profundal = rupture of the sweat duct deeper in the skin – can become infected/ cause problems with temperature regulation
   e. Treatment = cooling, remove excessive clothing

Question 98

Hair disorders - terminology

Answer 98

Hypertrichosis = excessive hair growth (rare in children – AE of cyclosporine, diazoxide) 
Hirsutism = androgen dependent male pattern of hair growth 
Hypotrichosis = deficient hair growth

Question 99

Trichotillomania

Answer 99

• Excessive (?obsessive) compulsive hair pulling
• Unusual pattern of broken hairs of varying lengths
• Often related to OCD
• Sometimes requires treatment with SSRI

Question 100

Alopecia - general

Answer 100

1. Traction/traumatic alopecia
   a. Hair ties or hairstyles
2. Alopecia areata
   a. Autoimmune hair loss
   b. Rapid and complete hair loss in round/oval patch on scalp
   c. Associated with atopy and autoimmune disease
   i. Vitiligo
   ii. T1DM
   iii. Thyroid
   d. Usually spontaneous remission

Question 101

Acquired diffuse hair loss

Answer 101

1. Telogen effluvium
   a. Very common
   b. Sudden loss of large amounts of hair
   c. Premature conversion of growing hair (anagen) hairs to resting hairs (telogen)
   d. Reversible, diffuse loss of mature hairs 2-3 months following an acutely stressful event (pregnancy, severe weight loss, major illness, surgery)
   e. Hair loss for 3-4 months before regrowth occurs
2. Anagen Effluvium (Toxic Alopecia)
   a. Severe diffuse inhibition of anagen follicles
   b. Diffuse and rapid loss of > 80-90% scalp hair
   c. Usually caused by an offending agent – radiation, chemotherapy, antimetabolits, mitotic inhibitors

Question 102

Acne

Answer 102

1. Contributing factors
   a. Abnormal keratinization of follicular epithelium  keratinized cells get impacted
   b. ↑sebaceous gland production
   c. Proliferation of proprionibacterium acnes
   d. Inflammation
2. Comedones
   a. Open comedones (blackheads) = dilated epithelium lined follicular sac, filled with lamellated keratinous material, lipid and bacteria
   b. Closed comedones (whiteheads) = more likely to get inflamed than open comedones
3. Treatment
   a. Retinoids – inhibit formation and number of microcomedones and reduce inflammatory lesions
   b. Benzoyl peroxide – antimicrobial agent
   c. Topical antibiotics – clindamycin , not effective as oral antibiotics
   d. Oral tetracyclines – reduce growth and metabolism of Propionibacterium acnes + have anti-inflammatory properties
   e. Hormonal therapy – OCP
   f. Isotretinoin (Accutane)
   i. For severe nodulocystic acne
   ii. Standard course is 4-5 months
   iii. Reduces size and secretion of sebaceous glands, normalizes follicular keratinization and prevents new microcomedone formation
   iv. Very teratogenic , contraindicated in liver disease

Question 103

Georgraphic tongue

Answer 103

a. Recurring disorder characterized by pink  red slightly depressed lesions with irregular, elevated, white or yellow borders
b. Lesions are areas of desquamation, pattern constantly changes; migratory
c. Predominantly on dorsum and lateral borders of anterior 2/3rd of tongue
d. Asymptomatic usually, may be painful when inflamed
e. Girls > boys
f. Aetiology unknown

Question 104

Fissured tongue

Answer 104

a. One marked central anterior-posterior fissure
b. Depth ranges from shallow to deep - deep may trap food debris which can cause inflammation or secondary fungal infections
c. 5% of general population
d. Common in T21

Question 105

Angular cheilitis

Answer 105

a. Erythema, fissures, erosions in corner of the mouth
b. Causes
i. Traumatic – lip-licking, pacifiers, salivation, drooling
ii. Skin disease – atopic dermatitis, contact dermatitis
iii. Staph/Strep/candida infection
iv. Vitamin deficiency = riboflavin B2, niacin B3, zinc, iron/B12/folate deficiency

Question 106

Gingival overgrowth

Answer 106

a. Hereditary
i. Idiopathic hyperplasia
ii. Onset in childhood
iii. Complicated by failure or delay of eruption of primary & permanent teeth
iv. Treatment = gingivectomy
b. Inflammatory
i. Longstanding gingivitis or mouth breathers
c. Infiltrative – leukaemia, particular AML
d. Drug induced – phenytoin, nifedpine, cyclosporine

Question 107

General scalp disorders

Answer 107

• Neonates have seborrheic skin -> cradle cap/ seborrheic dermatitis
• Children have inactive seborrheic glands -> eczema or tinea
• Psoriasis can occur at any age

Scalp Eczema
• Older children
• Scale is harsher, itchy
• Usual eczema treatment

Psoriasis
• Plaque like lesions
• Often occur on hair line

Question 108

Tinea capitus

Answer 108

• Most common fungal infection in children
• Cause = trichophyton tonsurans + microsporum
• Appearance
o Looks like scaling of the scalp, circumscribed alopecia with broken hair line at the scalp
o May develop lymphadenopathy, inflammation
• Diagnosis = woods lamp (trichophyton is negative), KOH fungal culture
• Treatment = antifungals

Question 109

Lichen Sclerosis - vulval

Answer 109

1. Epidemiology
   a. Occurs in pre-pubertal girls (or postmenopausal women)
   b. Can resolve with puberty OR undergo silent progression with scarring and atrophy, with recurrence later
2. Aetiology = unknown
3. Clinical manifestations
   a. Itchy ++
   b. Dyspareunia
   c. Anal problems; fissures, rectal bleeding, painful defecation
   d. Dysuria
   e. Classic: White, atrophic papules that become plaques
   f. May also be haemorrhagic, purpuric, ulcerated
   g. Labia minor > labia majora
   h. Excoriations/lichenification with scratching
   i. Architecture gets disrupted as the disease progresses
4. Diagnosis = biopsy
5. Risks = risk of SCC of the vulva
6. Treatment
   a. Good hygiene
   b. Lubricants
   c. Steroid ointments – potent, or calcineurin inhibitors (tacrolimus, pimecrolimus)

Question 110

Vulvovaginitis

Answer 110

(Perth ED on Google)

Vulvovaginitis is the general term which refers to many types of vaginal/vulva inflammation or infection.

Background
In prepubertal girls usually 2-8 years, non-specific vulvovaginitis is responsible for 25-75% of vulvovaginitis.

Causal factors of non-specific vulvovaginitis in prepubertal child
Unoestrogenised thin vaginal mucosa with lack of labial development
More alkaline pH (pH 7) than post-menarchal girls
Moisture to area (aggravated by synthetic fibre underwear, tight clothing, wet bathers, obesity, poor hygiene)
Irritants (e.g. bubble baths, shampoos, soaps, antiseptics).

Assessment
Signs: redness, swelling, bleeding
Symptoms: discharge, pruritis, dysuria

Ix: if mild, none, if severe/profuse discharge/concerns can do swab

Differential diagnosis
If persistent, offensive or bloody discharge, consider the following:
threadworm if pruritus (vulval and/or perianal) is prominent especially at night.
foreign body if chronic vaginal discharge, intermittent bleeding, offensive odour. Toilet paper commonest foreign body. Refer to paediatric gynaecologist as required.
specific organisms if discharge is profuse/offensive take an introital swab (most commonly strep).

Management of non-specific vulvovaginitis once the above differential diagnoses are excluded:
Explanation that symptoms should resolve within 2-3 weeks
Avoid excess moisture and irritants
Daily warm baths (not hot)
Add half a cup of white vinegar to a shallow bath and soak for 10 to 15 minutes
Pat dry
Review hygiene with child:
Emphasize wiping from front to back after bowel motions
May use wet wipes instead of toilet paper if sensitive
Cool compresses may relieve discomfort
Emollients (soft paraffin or a zinc oxide paste may help with pain and protect the skin
Steroid cream can be prescribed if severe excoriation / dermatitis
Consider treatment for threadworm.

Question 111

Nutritional skin disorders

Answer 111

1. Kwashiorkor
   a. Severe protein and essential amino acid deprivation
   b. Diffuse fine reddish brown scaling, tends to spare sun exposed skin
   c. Thin and soft nails and hair
2. Pellagra
   a. Deficiency of niacin/ tryptophan
   b. May be secondary to isoniazid, 6 MP, 5 FU
   c. Edema, erythema and burning of sun exposed skin
3. Scurvy
   a. Vitamin C deficiency / alcoholism
   b. Follicular hyperkeratosis and coiling of hair on upper arms, back and buttocks
   c. Stomatitis, epistaxis, erythematous gums
4. Vitamin A deficiency
   a. Visual changes
   b. Cutaneous changes – xerosis, hyperkeratosis, hyperplasia of the epidermis

Question 112

Erythroderma

Answer 112

1. Key points
   a. Defined as any inflammatory skin disease involving >90%
   i. Eczema
   ii. Psoriasis
   iii. Drug eruption
   iv. Lymphoma and leukaemia – less common
2. Complications
   a. Temperature imbalance – usually hypothermia but hyperthermia possible
   b. High output cardiac failure
   c. Fluid balance
   i. Loss by transpiration is much increased necessitating increased requirement
   ii. However overcorrection of fluid deficit may exacerbate cardiac failure
   d. DVT
   e. Hypoalbuminaemia and edema
3. Nutrition
   a. Increased requirement
   b. ‘Dermatopathic enteropathy’ decreasing absorption
   c. Increased Fe loss through skin scale
   d. Lymphadenopathy – may be dermatopathic
   e. Complications of underlying cause
4. Treatment
   a. Treat/remove underlying cause
   b. Manage underlying complications
   i. Often require admission
   ii. Rest very important
   iii. Soothing bland creams and/or mild topical steroid ointments

Question 113

Livedo reticularis

Answer 113

Umbrella term encompassing cutis marmorata, cutis marmorata telangiectatica congenita, primary and secondary livedo reticularis, and livedo racemosa

1. Key points
   a. Painless, cyanotic mottling in fishnet pattern
   b. Results from vasospasm or sluggish flow through arterioles – ischemia/infarction
   c. Affects extremities or trunk
2. Aetiology
   a. Physiological
   i. Cold exposure in pale children/infants
   b. Vasculitis
   i. PAN
   c. Autoimmune disease
   i. SLE
   ii. Raynauds
   iii. Antiphospholipid syndrome
   d. Hyperviscosity/thrombotic disease
   i. Hyperoxaluria
3. Treat = underlying cause

Question 114

HPV - bg

Answer 114

1. Virology
   a. DNA virus family - >130 subtypes
   b. HPV 1/2/3/4/27/57– skin warts
   c. HPPV 6 and 11 – 90% genital warts, recurrent respiratory papillomatosis
   d. HPV 16 and 18 – cervical cancer, detected in >70% women with cervical Ca
2. Transmission
   a. Physical contact – fomites, sexual contact, non-sexual contact
   b. Vertical to newborn
   i. Increase incidence in HPV amongst pregnant women with gestation 23% 3rd trimester
   ii. Either vertical in utero or intrapartum trasmission
   iii. Colonise infant for at least 6 weeks
   iv. Thought to persist and usually remain subclinical
3. Pathogenesis
   a. Infection of keratinocytes
   b. Invades basal epithelium
   c. Long term latent infection
   d. Can reactivate or persist
   e. Majority , HPV transient and asymptomatic

Question 115

HPV - sx

Answer 115

a. Skin warts
i. Prevalence 10%
ii. F>M
iii. Most common 12-16yrs
iv. Plantar, palmar
v. Spontaneous clearance without Rx in 40% at 2 years
vi. Management – salicylic acid, cryotherapy, laser therapy, imiquimod, bleomycin, retinoids, immunotherapy

b. Genital warts
i. Vulval, vaginal, urethral, perianal
ii. F>M
iii. Must think about sexual about but comparable incidence amongst sexually abused and non sexually abused children therefore suggesting vertical colonization (defined as <24months) and close contact as transmission

c. Recurrent respiratory papillomatosis
i. 1/100,000, perinatal transmission
ii. HPV 6 and 11, 11 more common and more severe
iii. Most common benign tumor that affects the larynx in children
iv. Recurrent growth of benign papillomas along epithelium of URT
v. Can grow to cause complete airways obstruction
vi. Hoarseness, dyspnea, cough, stridor, dysphonia, weak cry
vii. Diagnosis – laryngoscopy + biopsy
viii. Management – laser surgical removal, cidofovir or INF

d. “High risk” serotypes – HPV 16 and 18
i. Colonise the oral cavity in young children – bimodal, infants and adolescents
ii. Significance of oral colonization unknown
iii. Cause cervical dysplasia
1. Sexual transmission
2. Adolescent prevalence in sexually active adolescent 15-40%
3. Cervical squamous intraepithelial lesions
4. Cervical cancer (2nd most common cancer in females)

Question 116

Molluscum contagiosum

Answer 116

1. Key points
   a. Superficial skin disease caused by a pox virus (large double stranded DNA virus)
2. Clinical features
   a. Atopic dermatitis increases risk and makes this worse
   b. Small pearly papules with central depression
   c. Can be expressed, white cheesy material
   d. Usually painless but can be inflamed
   e. Usually face, trunk and limbs
   f. Severe disease in immunocomprimised (can be giant lesions)
3. Natural history
   a. Usually >1 year old but considered paediatric condition
   b. Present in swimming pools, sauna, spas etc.
   c. Transmission by direct contact
   d. Self resolves in 6-12 months usually
4. Differential diagnosis
   a. BCC
   b. Keratoancanthoma
   c. Histioplasmosis
   d. Coccidiodomycosis

Most children require no ix/rx

5. Diagnosis
   a. Usually clinical
   b. Biopsy – eosinophilic inclusions in the epidermis
6. Treat
   a. Cryo, laser, pin, curettage
   b. Podophyllotoxin, salicylates, potassium hydroxide, tretinoin

Question 117

Impetigo

Answer 117

1. Key points
   a. Most common skin infection in children
2. Aetiology
   a. Staphylococcus aureus – usually spreads from nose
   b. Group A strep – occurs approximately 10 days after acquisition
3. Classification

a. Non bullous
i. >70% cases
ii. Caused by both S. aureus and GAS
iii. Lesions begin on skin of face/extremities at sites of trauma (bite, abrasion, chickenpox, burns)
iv. Vesicle/pustule formation followed by honey coloured crusted plaques
v. Little pain or surrounding erythema
vi. No systemic symptoms
vii. Regional adenopathy, pruritis
viii. DDx = viruses (HSV, VZV), fungi (tinea corporis), arthropod bites, parasites

b. Bullous
i. Caused by S auerues producing Exfoliative toxins (ETA, ETB, ETD) -> blister superficial epidermis – hydrolyse human semoglein 1 (same target as Ab in pemphigus foliaceus)
ii. Infants/young children
iii. Skin, face, buttocks, trunk, perineum, extremities
iv. Flaccid, transparent bullae develop – rupture results in narrow rim of scale at the edge of a shallow, moist erosion
v. Develop on intact skin – no preceding trauma
vi. DDx = epidermolysis bullosa, early SSSS, pemphigus and pemphigoid

4. Complications
   a. Related to strep infection if cause – local suppurative disease (cellulitis, lymphadenitis, abscess etc), Scarlet fever, post strep GN
5. Treatment
   a. Topical mupirocin 2% (bactroban) if localised
   b. Oral antibiotics cephalexin with widespread involvement / lesions near mouth
   c. If unresponsive at 7 days, swab MCS and redirect therapy

Question 118

Cellulitis

Answer 118

1. Key points
   a. Infection + inflammation of loose connective tissue, limited involvement of dermis
2. Aetiology
   a. GAS, Staph aureus – most common
   b. Pseudomonas, aeromonas, legionella, mucorales, Cryptococcus = if immunocompromised or DM
3. Clinical Manifestations
   a. Usually predisposing trauma, surgery, skin lesion
   b. Oedema, warmth, erythema and tenderness
   c. Lateral margins tend to be indistinct
   i. Staph tends to be more localized
   ii. Strep pyogenes tends to spread more rapidly and be associated with lymphangitis
   d. Systemic features uncommon
   e. Complications
   i. Subcutaneous abscess, necrotizing fasciitis, bacteremia, osteomyelitis, septic arthritis, thrombophlebitis, endocarditis
   ii. Local suppurative complications or GN can occur with S pyogenes
4. Investigations
   a. Aspirate
   b. Blood culture
   c. 25% identify organism
5. Treatment
   a. Cellulitis in neonate – prompt full sepsis workup
   i. IV flucloxacillin or vancomycin + gentamicin or cefotaxime
   b. Infant or child younger than 5
   i. Blood culture if infant appears unwell, or < 1 year
   ii. If fever, lymphadenopathy or other constitutional signs are absent
6. Oral flucloxacillin or cephazolin
7. If MRSA suspected – clindamycin / vancomycin
8. If improvement not noted in 24-48 hours -> IV Flucloxacillin +/- vancomycin needed

Question 119

Erysipelas

Answer 119

• Superficial form of cellulitis caused by GAS

* Involves the upper dermis + superficial lymphatics (cf. cellulitis involving deeper dermis + subcutaneous fat)

Question 120

Staph scalded skin syndrome

Answer 120

1. Key points
   a. Neonates susceptible - renal excretion toxin reduced in neonates
2. Pathogenesis
   a. Dissemination of s. aureus exfoliative toxin
   b. NOT superantigen pathogenesis
   c. Act in zona glomerulosa of epidermis  cleavage of desmoglein 1 which normally anchor keratinocytes to each other  ruptured bullae
   d. Same pathogenesis as bullous impetigo
3. Clinical manifestations
   a. Source of infection may be obvious – e.g. omphalitis
   i. Not present at birth
   ii. Onset Day 3-7 of life
   b. Systemically unwell
   i. Sick infant
   ii. Present with irritability, fever, blanching erythema around mouth
   c. Skin
   i. Superficial blisters
   ii. Blisters (particularly in areas of mechanical stress) appear 1-2 days later – flexural, knees, hands, buttocks
   iii. Nikolsky’s sign positive = gentle pressure results in separation of upper epidermis & wrinkling of skin
   iv. Mucous membranes NOT involved
   v. Flaky desquamation as lesions heal
   vi. No scarring because cleavage plane is intradermal
4. Investigations
   a. Intact bullae sterile
   b. Culture from original site of infection
5. Histology
   a. Will distinguish from TEN + SSSS
   i. SSSS = intraepidermal cleavage plane
   ii. TEN = subepidermal cleavage plane and epidermal necrosis
6. Management
   a. Flucloxacillin
   b. Vancomycin

Question 121

Necrotising fasciitis

Answer 121

1. Key points
   a. SC tissue infection, involves deep layer of superficial fascia – majority are polymicrobial in nature
   b. Necrotizing infection defined as when inflammation leads to tissue destruction, not responsive to antibiotics and usually needs debridement
2. Aetiology
   a. S aureus
   b. Streptococcal spp
   c. Clostridium
   d. Klebsiella
3. Risk factors
   a. DM, neoplasia, peripheral vascular disease, recent surgery/trauma, immunosuppressed
   b. VZV infection – predisposes to Strep infection
4. Clinical Manifestations
   a. Anywhere on body, typically trunk and perineum
   b. Local swelling, erythema, tenderness & heat  fever, pain, systemic signs out of proportion to cutaneous findings
   c. Lymphangitis & lymphadenitis usually absent
   d. Skin changes appear over 24-48 hrs as nutrient vessels are thrombosed and cutaneous ischaemia occurs  initial erythema and oedema
   e. Formation of bullae  tissue goes from red  purple  blue
   f. Skin anaesthesia  finally frank tissue necrosis with sloughing
   g. Crepitations associated with clostridium or gram negative enterobacteriae
   h. Can lead to shock, organ failure and death
5. Investigations = surgical exploration
   a. Necrotic fascia and subcutaneous tissue are gray and offer little resistance
   b. Gram staining of tissue
6. Treatment
   a. Early supportive care, surgical debridement and IV Abx
   b. Devitalised tissue should be removed, may be repeated until all gone
   c. IV Abx – vancomycin + quinolones
7. Prognosis
   a. GAS associated with higher mortality and toxic shock syndrome – 60% mortality

Question 122

Cellulitis vs erysipelas

Answer 122

Erysipelas
Upper dermis and superficial lymphatics
Sharply demarcated
Raised
Typical “butterfly rash” on face
May involve the ear (Milian’s sign – distinguishing feature)
Acute onset with systemic features
Almost always strep pyogenes

Cellulitis
Deep dermis and fat
Less well demarcated
Flat
Unilateral
Typically lower limb
Periorbital
Indolent course
Group A strep
Staph aureus
Haemophilus influenzae

Same treatment

Question 123

Folliculitis

Answer 123

a. Usually staph (hot tubs – pseudomonas)

Folliculitis is a common skin condition in which hair follicles become inflamed. It’s usually caused by a bacterial or fungal infection. At first it may look like small red bumps or white-headed pimples around hair follicles — the tiny pockets from which each hair grows.

Question 124

Cutaneous TB

Answer 124

a. Usually occurs when m. tuberculosis/ m. bovis gains access to skin / mucous membranes through trauma
b. Can manifest as painless ulcer, adenoathy, scrofuloderma (lymphadenitis which spreads and perforates skin surface)
c. May reactivate/ progress to acute military disease

Question 125

Tinea/pityriasis versicolour

Answer 125

1. Aetiology = dimorphic yeast Malassezia globose
   a. Part of indigenous flora
   b. Also implicated in
   i. Follicular pityriasis
   ii. Seborrheic dermatitis and pityriasis capitis
2. Clinical manifestations
   a. White individuals = reddish brown
   b. Black individuals = hypopigmented or hyperpigmented
   c. Macules covered with fine scale
   d. Usually perifollicular location, enlarge and merge to form confluent patches
   e. Most commonly neck, upper back and upper arms
   f. Facial lesions common in adolescents
   g. Little or no pruritis
   h. Involved areas do not tan after sun posure
3. Investigations
   a. Wood’s lamp examination = yellowish gold fluorescence
   b. KOH preparation = diagnostic
   i. Groups of thick-walled spores and short, thick, angular hyphae resembling spaghetti and meatballs
4. Treatment
   a. Topical therapy = selenium shampoo, ketoconazole shampoo
   b. Antifungal creams
   c. Oral therapy = ketoconazole or fluconazole

Question 126

Dermatophytoses

Answer 126

1. Aetiology
   a. Trichophyton
   b. Microsporum
   c. Epidermophyton
2. Epidemiology
   a. Predisposing conditions = diabetes, malignancy, immunosuppression, elevated cortisone
3. Clinical manifestations

a. Tinea capitis
i. Usually in small children
ii. Red, scale well demarcated patch on scalp
iii. ‘Black-dot ringworm’ – small circular patches of alopecia
iv. Diffuse scaling, with minimal hair loss
v. Kerion = severe inflammatory response resulting in boggy granulomatous masses
vi. Fever, pain and regional adenopathy
vii. Secondary staph infection
viii. Treatment = griseofulvin microcrystalline, itraconazole, terbinafine

b. Tinea corporis
i. Itchy, circular red scaling patches with central clearing – ring shaped red ovals
ii. Caused by most dermatophytes
iii. Does NOT fluoresce with woods lamp
iv. Treatment
1. Topical antifungal agents (imidazoles, terbinafine, naftifine)
2. Oral griseofulvin, itraconazole
3. Do NOT use combination steroid cream

c. Tinea crusis
i. Red patch on inner aspect of one or both thighs
ii. Can be chronic and progressive
iii. Scrotum typically spared
iv. Treatment
1. Wear loose cotton underwear
2. Topical antifungal = imidazole

d. Tinea pedis
i. Red, progressive, itchy erosions or scales between toes with extension onto sole, side of foot
ii. Treatment
1. Avoidance of occlusive footwear
2. Drying after baths
3. Topical antifungal powder = zinc undecylneate, imidazole

e. Tinea unguium
i. Distal subungual (tricophyton rubrum + mentagrophytes) = focal onycholysis under distal nail plate
ii. Proximal subungal (tricophyton rubrum) = affects the underneath of nail (immunocompromised)
iii. White superficial (tricophyton mentagrophytes) = diffuse/ speckled discolouration
iv. Treatment = itraconazole, terbinafine

f. Tinea incognito
i. Altered appearance of tinea due to treatment with topical steroids

4. Diagnosis
   a. KOH scrapings
5. Treatment
   a. Do not use combination steroid and antifungal creams – alters course of disease and no added benefit
   i. Nystatin should be used for cutaneous candida infection NOT dermatophytes
   b. Topical antifungals for all – terbinafine (superior to azoles)
   i. If chronic infection or resistant to topical treatment; oral terbinafine or azole recommended for 2-6 weeks
   ii. EXCEPT scalp and nail (6-12 weeks of oral terbinafine/griseofulvin and topical ketoconazole)

Question 127

Onychomycosis

Answer 127

1. Definition = Nail infection caused by any fungus including yeasts and nondermatophyte spp
2. Risk factors
   a. Swimming pools
   b. Older age
   c. Tinea pedis
   d. Diabetes
   e. Immune deficiency
   f. Genetics
   g. Living with people who have it
3. Abnormal appearing nails = 50% due to onychomycosis
   a. Others – psoriasis, eczema, iron deficiency, lichen planus etc
4. Diagnosis
   a. Potassium hydroxide examination of scrapings of nail bed
   b. Nail culture
5. Treatment
   a. Terbinafine 6-12weeks
   b. Baseline AST/ALT prior

Question 128

Candida infections

Answer 128

1. Key points
   a. Ubiquitous in environment
   b. Not part of the indigenous skin flora – frequently transient on skin and may colonise alimentary tract and vagina
   c. Environmental conditions such as temperature and humidity increase frequency of isolation on the skin
2. Clinical manifestations

a. Chronic mucocutaneous candidiasis
i. Rare condition
ii. Candida infection persistent and widespread
iii. Associated conditions
1. Genetic predisposition
2. Endocrine – hypothyroid, hypoparathyroid, Addison’s, DM
3. Immune deficiency – T cell defects, antibody deficiency (APECED/APS-1)
4. Systemic – myasthenia gravis, myositis, aplastic anaemia
iv. Clinical features
1. Oral candida
2. Onychomycoses
3. Widespread candida of skin, especially scalp, trunk, hands and feet
4. Granulomas – mouth, skin and nails
5. Susceptible to tinea and HPV infection
v. Treatment - Azole

b. Vaginal candidosis
i. Inhabitant of vagina of 5-10% of females
ii. Risk factors = antibiotics, corticosteroids, diabetes, pregnancy, oral contraceptives
iii. Clinical manifestations = cheesy white plaques on erythematous vaginal mucosa
iv. Treatment = nystatin or imidazole vaginal tablets, suppositories, creams or foam

c. Candidal diaper dermatitis
i. Clinical manifestations
1. Intensely erythematous, confluent plaque with scalloped border and sharply demarcated edges, with numerous papules and vesicular pustules
2. Satellite pustules hallmark of candida
3. Perianal skin, inguinal folds, perineum and lower abdomen usually involved
ii. Treatment
1. Imidazole cream BD
2. Corticosteroid if severe
3. Barrier cream and other management of diaper rash

d. Intertriginous (skin folds) candidosis
e. Perianal candidisosis

Question 129

Scabies

Answer 129

1. Pathogenesis
   a. Caused by mite, sarcoptes scabiei
   b. Burrow into epidermis, faeces and ova load by females
   c. Lead to itch and secondary infection from scratching
   d. Skin eruption due to hypersensitivity reaction
   e. Transmitted skin to skin contact
   f. Incubation 3 weeks but reinfection much faster
2. Clinical manifestations
   a. Erythematous, itchy papules
   b. VERY itchy, especially at night
   c. Can develop into vesicles, pustules and crusting
   d. Widespread involvement – hands, feet, wrists and face
   i. Especially web spaces, flexor aspect of wrists and elbows, axilla, male genitals and womens breasts
3. Diagnosis
   a. Usually clinical
   b. Can do skin scrapings where mites/faeces/eggs seen on microscopy
4. Treatment
   a. 5% permethrin lotion topically first line – wash off after 8-12 hours
   i. Active on all stages of parasite lifecycle
   ii. Not for children <2 months or pregnancy
   b. Oral ivermectin
   c. Total eradication of the entire household with permethrin + washing all linen and clothes in hot water + clothes line to dry
   d. Return to school/day care once treatment complete

Question 130

Lice

Answer 130

1. Types of lice
   a. Pediculus humanus corporis (body / clothing)
   b. Pediculus humanus capatis (head lice)
   c. Pubic phthirus pubis
2. Pathogenesis
   a. Female lice live for 1-month, deposit 3-10 eggs daily on the human host
   b. Body lice tend to lay eggs near semas of clothing
   c. Ova hatch in 1-2 week, take 1 further week to mature
3. Treatment
   a. Head lice = malathion 0.5% in isopropanolol left on for 12 hours
   i. Treat all members
   ii. Clean clothing and bed linens
   b. Pubic lice = 10 minute application of pyrethrin preparation

Question 131

Lice

Answer 131

1. Types of lice
   a. Pediculus humanus corporis (body / clothing)
   b. Pediculus humanus capatis (head lice)
   c. Pubic phthirus pubis
2. Pathogenesis
   a. Female lice live for 1-month, deposit 3-10 eggs daily on the human host
   b. Body lice tend to lay eggs near semas of clothing
   c. Ova hatch in 1-2 week, take 1 further week to mature
3. Treatment
   a. Head lice = malathion 0.5% in isopropanolol left on for 12 hours
   i. Treat all members
   ii. Clean clothing and bed linens
   b. Pubic lice = 10 minute application of pyrethrin preparation