Dermatology Flashcards
What is bullous pemphigoid
Autoimmune sub-epidermal condition characterised by large, tense blisters found on the limbs, trunks and flexors
Bullae/erosions may be also found on oral/genital mucosa
What autoantibodies are present in bullous pemphigoid
BP antigen II and I
Treatment of bullous pemphigoid
Steriods
Supportive measures
Risk factors for developing bullous pemphigoid
Previous chronic inflammatory skin conditions (e.g. lichen planus or psoriasis)
Drugs
- furosemide
- antibiotics
- NSAIDs
Neurological disease
- PD
- dementia
- Epilepsy
Causes of bullous eruptions
Congenital
Strep infection
Staph scalded skin syndrome
TEN
Diabetic bullae
CKD
Haemodialysis
Barbituate overdose
Immunological
What is erythema multiforme?
Presents as eruptions of multiple lesions, which are maculopapular, target shaped rashes but can appear in various forms (hence the name multiforme)
Where can erythema multiforme occur?
Anywhere on the body
Palms
Soles
Oral mucosa
What may there be a history of with erythema multiforme?
Viral illness
Where does the rash usually start and spread with eyrthema multiforme?
Starts distally
Spreads proximally
What is Koebeners phenomenon?
Lesions appearing on areas of previous skin trauma
Differentials of erythema multiforme
Insect bites
SJS
TEN
Drug eruption
Dermatitis
Bullous pemphigoid
Pemphigus
Dermatitis herpetiformis
What is neurofibromatosis?
A genetic condition characterised by lesions of the skin, CNS and skeleton
Types of neurofibromatosis
Type I
Type II
Schwannomatosis
Genetics of neurofibromatosis type I
Autosomal dominant inherited disorder
Caused by mutation in the neurofibromin gene (NF1) on chromosome 17
Presentation of NF1
Often presents in first year of life and increase in number with age
Leads to multiple tumours that grow along the NS anywhere in the body
Skin lesions
- multiple neurofibromas (skin coloured lesions) and cafe au lai macules
- freckling, particularly in skin folds
Neuro dermatofibromas arise from nerve trunks and can cause paraesthesia when pressed
Lisch nodules (seen on eye with slit lamp)
Short stature
Macrocephaly
Around 30% develop
- Mild learning disability
- Acoustic neuromas
- epilepsy
Rare assosiation of NF1
Phaechoromocytoma
Main difference NF2 vs NF1
CNS tumours being more characteristic than skin lesions
Presentation of NF2
Bilateral acoustic neuromas are characteristic
Meningiomas
Glial cell tumours
Usually present with deafness in their 20s; tinnitus, veritgo
Genetics of NF2
Mutation found on chromosome 22
Can be autosomal dominance or de novo (up to 50%)
Treatment of acoustic neuroma
Surgical excision
Mean survival from diagnosis of NF2
15 years
What is schwannomatosis?
Occurence of multiple tender cutaneous schwannomas without the vestibular neuroma assosiated with NF2
Often a very large tumour load requiring assessment with MRI
Is life expectancy affected in schwannomatosis?
No
Which NF is more common?
Type 1
Presendation of schwannomatosis
Pain
Related or unrealated to masses
Paraesthesia and weakness
Genetics of schwannomatosis
Medatiations of tumour suppression genes such as SMARCB1 and LZtr1
Complications of NF
Tumours of optic nerves (gliomas) (15% of childre with NF1)
Scoliosis
Osteoporosis
Epilepsy
Increased risk of brain tumours, leukaemias and other malignancies of neural crest origins
Malignant change if there are peripheral sheath tumours in NF1 (assosiated with poor survival)
First line treatment for scabies
Permethrin cream
What is erythema nodosum
Acute panniculitis (inflammation in the fat) that produces tender nodules or plaques on the shins and occassionally elsewhere
Assosiations of erythema nodosum
Idiopathic
Sarcoidosis
Pregnancy
IBD
Strep infections
TB
Treatment with sulfonamides or OCP
Treatment of erythema nodosum
NSAIDs
What is pyroderma gangronosum assosiated with
IBD
Vasculitis
Haematological malignancy
Presentation of pyoderma gangrenosum
Deep ulcer
Violet border
What is koebeners phenomenon
New disease lesions develop at the site of skin injury
What coniditons provide a true koebeners response
Psoriasis
Vitiligo
Lichen planus
Rash in lichen planus
Pigmented
Itchy
Diseases assosiated with PLEVA
Toxoplasmosis
EBV
HIV
CMV
Parovirus
Staph A septicaemia
Group A beta haemolytic strep infection
Presentation of PLEVA
Initial area of erythema
Develops rapidly into multiple pus filled papules
What is onchyolysis
Seperation of nail bed from nail plate
Causes of onchyolysis
Psoriasis
Trauma
Infection
Drugs - tetracycliens, psoratens
Thyrotoxicosis
What is bowens disease
A form of SCC
Presents as a red scaley plaque
How does polyphyria cutanea tarda occur
Bullous eruptions after exposure to sunlight
Eruptions heal into scarring and milia
Photodistribution of the rash
Investigation of polphyria cutanea tarda
Clinically
High levels of urinary uroporphyrin
How can remission of polyphyria cutanea tarda be induced
Venesection
Presentation of rash in dermatomyositis
Red or volacious periorbital eruption known as the helitrope rash
May be assosiated oedema
Linear volacious changes over dorsal aspect of fingers
Shawl sign - erythema over upper back and posterior neck
Weakness of major proximal muscles
Investigations of scabies
Ink test
What is pemphigus vulgaris
Mucosal involvement with ulceration
Flaccid blisters (on trunk in particular)
What would be found in a biopsy for pemphigus vilgaris
Intercellular IgG deposition
What is the test for marfan syndrome
Fibrillin 1 (FBN1) gene testing
What is pseudoxanthoma elasticum
Rare genetic disease causing systemic calcium deposition and fragmentation of elastic tissue
Complications of pseudoxanthoma elasticum
Central blindness
CVS events
GI bleeding
Skin manifestations of pseudoxanthoma elasticum
Multiple small yellow papiles, possibly joining into larger patcges
Later in the disease, skin can become lax, wrinkled and hanging in like fold like appearances e.g. on upper arms
on neck (commonest), inside elbows, back of knees, umbilicus, groin
Oral, genital and rectal mucosa
Diagnosis of pseudoxanthoma elasticum
Skin biopsy
Drugs that can cause photosensitivity
Doxycycline
NSAIDs
retinoids
Diuretics
CVS drugs (amoidarone, enalapril, quinidine, diltiazem)
Sulfounryea drugs
Phenthoiazines
What can immunosuppresision cause in relation to shingles?
Muti-dermatomal
Disseminated disease
In the pathogenesis of psoriasis, which cell type is most implicated in the inflammatory response
T lymphocytes
What drugs can worsen psoriasis
Beta blockers
Anti-malarials
Lithium
Withdrawl of oral corticosteriods, especially if sudden
What can precipitate guttate psoriasis
Strep infection
What is melasma
Hormonally stimulated increase in melaogensis that mainly appears on the face
What can worsen melasma
Sun exposure
COCP
Pregnancy
Where does melasma occur mainly
On the face
Secondary syphillis presentation
Polymorphic rash
- particularly on palms and soles of feet
Presentation of primary syphillis
Painless ulcer
What causes pellagra
Chronic vitamin B3 deficiency
Presentation of pellagra
3Ds
- photosensitive dermatitis
- diarrhoea
- dementia
What condition can pellagra be seen in
Carcinoid syndrome
Skin manifestations of systemic sclerosis
Taunt, shiny skin
Telangiectasis
Salt and pepper discolouration
Ulceration
Sclerodactyly
What is necrobiosis lipoidica
Unusual complication of DM
May also occur in non diabetic patients
Small vessel damage leads to partial necrosis of detmal colleagen and connective tissue, with a histiocytic cell response
Presentation of necrobiosis lipoidica
Mostly on the legs
Erythematous plaques
Gradually develop into yellow brown waxy discolouration
Marked atrophy and prominant telangiectasia
Poor prognostic indicators of malignant melanoma
Depth (breslow thickness)
Ulceration
Most common CVS complications seen in pseudoxanthoma elasticum
Accelerated atherosclerosis
Mitral valve prolapse
Eye characterisation of pseudoxanthoma elasticum
Angioid streaks
Presentation of pemphigoid of pregnancy
Rare immunobullous disease
Tends to begin second trimester but can occur whenever
Some cases, worsens after delivery
Tense blisters
Investigation of pemphigoidof pregnancy
Biopsies for histology and immunoflorencence
Treatment of pemphigoid of pregnanct
PO steriods
Presentation of polymoprhic eruption of pregnancy
Pruritic and urticated papules and plques
Itchy
Blistering unusual
Spares the umbilical area
Bioppsy results of dermatitis herpetiformis
IgA
Presentation of pemphigus
Flaccid blisers that erode / erupt easily
Blisters pemphigus vs pemphigoid
Pemphigus - flacid blisters that erode / erupt more easily
Pemphigoid - blisters tense and do not rupture easily
Age pemphigus vs pemphigoid
Pemphigus - 40-60 y/o
Pemphigoid - older
Investigation of pemphigus
Immunofloureosecne
- antibodies to the cells in the epidermis
Anti-desmoglein antibodies (type I and III) in blood samples
Management of chronic spontaentous urticaria if two antihistamines arent controlling symptoms
Monteleukast
- thought to be useful in reduction of duration and severity of episodes
Presentation of pityriasis rosea
Herald patch
Followed by widespread similar red patches with a fine collaret of scale
Can be asymptomatic
Investigation of pityriasis rosea
Clinical
Treatment of pityriasis rosea
COnservative
Rash usually resolves up to 12 weeks later
Antibodies seen in paraneoplastic pemphigus
Envoplakin
Periplakin
Bullous pemphigoid antigen I
Desmoplakin
Desmoplakin II
Alpha 2 macroglobulin like 1
WHat does an older patient with intact blisters on their limbs indicate
Bullous pemphigoid
Presentation of HSP
Purpura in dependent areas (buttocks and legs) (vasculitic rash)
Abdo pain and vomiting
With or without upper gi haemorrhage
Nephritis (less commonly nephrotic syndrome)
What age do oyu commonly see HSP
4 -15 y/o but can occur at any age
Pathophysiology of HSP
Mediated by IgA
Deposited in affected organs
Antigen triggers of HSP
Drugs
Foods
Immunisation
Various infections
Treatment of HSP
Supportive
Presentation of molluscum contagiosum
Crops of firm, smooth umbilicated papules
Treatment of molluscum contagiousum
Cryotherapy
Can resolve spontaenously up to 18 months
Treatment of peristomal pyoderma gangrenosum
Topical tacrolimus
What HLA subtype is most assosiated with chronic plaque psoriasis
HLA-CW6
HLA subtype related to T1DM
HLA-DR3
WHat HLA subtype is related to psoriatic arthritis and pustular psoriasis
HLA-B27
What can worsen skin manifestations of NF1
Pregnancy
Presentation of a sebacous cyst
fluid filled lesion
skin smooth and intact on top
painless
occassionally become painful and inflammed
discharge caseous material
Are macules raised or flat
flat
Presentatio n of tuberculoid leprosy
Hypopigmented areas of skin
Accompanied by reduced sensation
Investigation of leprosy
Mycobacterium leprea on skin biopsy or slit-skin smear
Treatment of acne
- Topical antibiotics
- Oral antibiotics (3 month trial - then trial another antibiotic)
- Topical retinoid
- Oral retinoid
Causative orgganism of lymes disease
Borrelia Burgdorferi
Presentation of dermatitis herpatiformis
Vesicles / blisters (quickly excoriated so may not be seen)
scaly itchy plaques
Who is zinc deficiency commonly seen in
alcoholics
Presentation of zinc deficiency
Anorexia / lethargy
Diarrhoea
Growth retardation
Delayed sexual maturation
Hypogonadism / hypospermia
Intellecutal disability, impaired nerve conduction and nerve damage
Hepatomegaly
Immune disorders
Susceptibility to infections
Alopecia / dermatitis / paronychia
What is erysipelas
A superficial form of cellulitis
Features of erysipelas
Distinctive, warm, red tender skin lesion
Induration and is sharply defined
Raised, rapidly advancing border
Vesicles or bullae may develop
Face is commonly affected
Causative organism for erysipelas
Group A beta haemolytic strep (strep pyogenes)
another name for vitamin B3
Naicin
Treatment of pyoderma gangrenosum
- Very potent topical steriods
- Prednisolone
- Ciclosporin or other immunosuppressive agents
- Dapsone
- Tetracycline Abz
Treatment of venous ulceration
Compression bandaging
Where is acral lentigious melanoma seen
Sole of the foot
Occassionally on the palm of the hand
Presentation of acral lentigious melanoma
Normally seen on sole of the foot
Can be seen in the palm of the hand
Irregulatly pigmented macule, but thicker palpable areas may appear if it progresses
Size can range from a few mm to a few cm
When does lentigo maligna melanoma tend to present
Chronically sun exposed skin
Typically the face
Features of nodular melanoma
Aggressive
Grows deeper
Presents as a papular or nodular lesion
Deeply pigmented but can be amelanotic
Where does subungal melanoma occur
Nail apparatus
What is the most common subtype of melanoma
Superficial spreading melanoma
Inheritance of dariers disease
AD
Presentation of dariers disease
Apparent in early adulthood
Warty papules and plaques in seborrhoeic areas (e.g. central chest and back, scalp, flexures), palmar pits and nail dystrophy
Secondary infection of the lesions can lead to crusting and malodour
Treatment of dariers disease
Retinoid acitretin can be used to treat symptomatic cases
What is wickhams strae and what condition is it characteristic of
Fine, white lacy pattern over the papules
Characteristic of lichen planus
What is erypsillas assosiated with
systemic upset (fevers, chills)
Where does SCC occur
Chronically sun exposed areas such as face and lips
May arise from
- actinic keratosis
- Bowens disease
- chronic wounds
- areas of inflammation (known as marjolins ulcer)
What is PUVA
A type of ultraviolet light therapy (phototherapy)
Presentation of kapsois sarcoma
Red, purple or brown cutaneous nodules or plaques, lesions may occur in mouth or internal organs
Typically affects legs, head and neck
Lesions are usually asymptomatic
WHat antibody is present in virtually all patients with SLE at some stage
anti-nuclear antibody
Presentation of sweets syndrome
Skin lesions are
- plum coloured
- may be papules, plaques or nodules
Mucosal involvement and blistering may occur
Often fever and neutrophilia
Diagnosis of sweets syndrome
Skin biopsy
What condition makes up the majority of cases of patients with paraneoplastic pemphigus
NHL
What pattern does pityriasis rosecea occur in
Christimas tree distribution
What is rosacea often assosiated with
Rhinophyma (enlarged sebaceous cysts around nose)
Ocular rosacea
- conjunctivitis
- blepharitis
- keratitis
Treatment of rosacea
Topical azelaic acid
Topical ivermectin
Brimonidine
Doxycycline
Tetracycline
What is more severe, TEN or SJS
TEN
Presentation of TEN/SJS
Flu like prodrome
Followed by a red/purple rash which then blisters/forms bullae
Affects the skin, mucous membranes, eyes and genitalia
Treatment of TEN/SJS
Identify and remove/treat underlying cause
Analgesia
Fluids
Corticosteriods
Abx
80% of TEN/SJS is caused by what
Drugs
What drugs can precipitate SJS/TENS
Allopurinol
Cephalosporin
NSAIDs
Phenytoin
Carbamazepine
Sulfa group Abx
Sulfasalazine
Sertraline
Antivirals
Risk factors for developing TENS/SJS
Previous Hx
Family Hx
Genetic predisposition - HLA b1502 or HLA b1508 genes
Pathology of SJS/TENS
Type IV hypersensitivity reaction
SCORTEN system for severity of TENS/SJS includes
Age > 40
Prescence of malignancy
HR > 120
Epidermal detachment > 10% body surface
Urea > 10
Glucose > 14
Bicarb < 20
Treatment of lichen sclerosus
Reducing course of topical Clobetasol 0.05%
What is the most useful cytokine to target in the treatment of psoriasis with potent monoclonal antibodies
IL17
What should we check for if there is angio eoedema in the abscence of urticaria
C1-esterase inhibitor deficiency
ACE inhibitor induced angiooedema
How can rosacea be distinguished from acne
Abscence of comedones
Distrbution of the rash (almost always confined to the face)
Lack of scarring
Effect of sunlight (brings an improvement in acne)
Age (rosacea more common > 40)
What is erythroderma
Any inflammatory skin condition covering in excess of 90% of the body surface
Causes of erythyroderma
Eczema
Psoriasis
Drug eruption
Cutaneous lymphoma
Pityriasis ruba pilaris
WHat causes pityriasis versiolour
Fungus malassezia globosa
When is malassezia globosa commmon
Area of skin covered by occlusive clothing or is more subject to sweating
More likely to occur in hotter weather
Whta toxin does staph A produce in recurrent skin infections
PVL
Signs of melanoma in an existing mole
Asymmetry of pigmentation
Irregularity in shape and border
Multiple colours
Enlargement
Darkening
Bleeding without trauma
What is discoid lupus erythematous also known as
Chronic cutaneous lupus erythematous
what is tyolosis assosiated with
carcinoma of the oesophagus
Where does lichen planus commonly affect
Wrist and ankles
Treatment of cutaneous leishmaniasis
Sodium Stibogluconate
Features of Behects syndrome
Recurrent orogenital ulceration
Uveitiis
Arhtiritis
Pathology of behects disease
Autoimmune
Assosiations - HLA B12, B51 and B5
3 features of acute intermittent porphyria
Abdominal pain (may mimic acute abdomen)
HTN
Psychiatric disturbance
How does AIP
Defect in porphobiligen deaminase
Treatment of acute attacks of AIP
IV haem arginate
What is often seen (and in the diagnostic crtieria) for NF1 that you would see on slit lamp examination
At least two Lisch nodules (iris hamartomas)
Treatment of acne rosacea
Topical azelaic acid
How long does it take for kertatinocytes to transform to anucleate corneocytes
3 days
What can occur at the edge of chronic venous ulcers
Squamous cell carcinomas forming at the margin
When does guttate psoriasis occur
approx. 2 weeks after a streptococcal throat infection
(more common in patients with a FH of psoriasis)
WHat is the main trigger for acne in young women
Follicular epidermal hyperprolileration
Treatment for acne rosacea with assosiated frequent facial flushing
Topical brimonidine
