Dermatology

Question 1

Atopic eczema course

Answer 1

Onset often in first 12m (after 2m)
1/3 develop asthma
75% resolve by 16y

Question 2

Atopic eczema CF

Answer 2

Infants mostly face/scalp/trunk, older children mostly flexor surfaces + friction surfaces e.g. neck

CF: pruritus - excoriations - erythema, weeping, crusted lesions, lichenification
-regional lymphadenopathy in exacerbations

Exacerbation causes: bacterial infection (usually S aureus), viral (e.g. HSV-less common but can cause an extensive vesicular reaction eczema herpeticum which is an emergency), heat/humidity, ingestion of an allergen e.g. egg

Question 3

Management of atopic eczema

Answer 3

• Avoid irritants like soap, biological detergents, pure wool clothes - prob have to try different things
• Could trial dietary eliminations to common allergens like egg/cow milk. For 4-6w to see response, dietician adv
• Cut nails to reduce scratching, mittens at night in young
• Emollients - liberal application at least 2x per day + after bath; in bath to use as a soap (still cleans just doesn’t foam), ointment better for night as more moisture but greasy
• Topical steroids: mild (1% hydrocortisone), stronger for acute exacerbations e.g. eumavate (moderate)/betnovate (potent)/dermovate (v potent). Don’t do unnecessarily but obviously if child needs it then they need it
• Immunomodulators for >2yo: e.g. topical tacrolimus
• Infections: topical/oral Abx + hydrocortisone depend on severity; eczema herpeticum need systemic acyclovir
• Itch suppression - oral non-sedating antihistamines

Question 4

Urticaria

Answer 4

Activation of mast cells - mediators like histamine. If involves deeper tissues - angioedema

• Acute: viral infection (rash for days) or allergy (rash for hours, risk of anaphylaxis)
• Chronic idiopathic: intermittent for at least 6w, usually non-allergenic
• Physical: to cold, delayed pressure, heat, solar, cholinergic (from sweating), exercise, NSAIDs/aspirin

M: non-sedating antihistamines (may need high dose), refractory cases LTRA or anti-IgE antibody (omalizumab) used

Question 5

Milia

Answer 5

Small pearly/yellow papule on babies

normal, last a few weeks

due to keratin + sweat glands not being fully formed

Question 6

Erythema toxicum neonatorum

Answer 6

harmless rash on day 2-3 neonate, goes by 1w

small firm yellow/white pustules on top of erythematous skin, pus contains eosinophils

anywhere except pals + soles

Question 7

Naevus simplex - stork bite marks

Answer 7

distended dermal capillaries - usually fade

Question 8

Cradle cap

Answer 8

common, harmless, no itching (if symptoms consider atopic dermatitis) - large greasy yellow-brown scales on scalp/ears/face/nappy area/skin folds
usually clear on own, massaging scalp with baby oil will help loosen

Question 9

Strawberry naevus

Answer 9

cavernous haemangiomas

RF: female, low birth weight, prematurity, multiple gestations

Question 10

Port-wine stain

Answer 10

vascular malformation causing superficial dermal capillary ectasia

usually on face, pink/red/purple patches, tend to persist + darken with age

laser if disfiguring

Question 11

Mongolian blue spot

Answer 11

Call slate grey naevi now!!

Blue/black pigmented lesions on buttocks/base of spine (trapped melanocytes in dermis)

more common in Afro-Caribbean or Asian babies

Fade in first few fews

Question 12

Irritant contact dermatitis

Answer 12

commonest cause of nappy rash

cf: W-shaped lesion (spares folds, whereas other things affect folds), lower abdo/top of thighs, erythematous, may look scalded. if severe can have erosions/ulcers

made worse with baby wipes + cloth diapers as reduced absorption (so more contact with the irritant urine/poop), humidity, friction

m: keep area clean + dry, zinc oxide ointments??, emollients, if severe mild topical steroids.
not using a nappy would help but they obviously need to

Question 13

Perineal candidiasis

Answer 13

Widespread erythematous sharply-bordered area, satellite papules/vesicules
often d’td over anterior perineum + perianal region
triggers include systemic abx
m: gentle cleansing, anti fungal e.g. nystatin (usually topical)

Question 14

Molluscum contagiosum

Answer 14

Caused by DNA poxvirus

CF: small skin-coloured pearly papule with central umbilication, usually multiple, may occur in clusters. may be pruritic or tender or asymptomatic

M: usually go on their own over about a year, may use cryo in older children

Question 15

Effect of prematurity on the skin

Answer 15

thin skin
poorly keratinised
higher transepidermal water loss
impaired thermoregulation as less SC fat
cannot sweat until a few weeks old

Question 16

Bullous impetigo

Answer 16

blistering impetigo usually due to S aureus

m: systemic abx like fluclox

Question 17

Large melanocytic naevi

Answer 17

may need excision due to risk of MM

Question 18

Albinism

Answer 18

types: oculocutaneous, ocular or partial

Cf: depigmented skin, lack of fixation reflex due to lack of pigment in iris+retina, frowning due to nystagmus + photophobia, severe visual impairment

Question 19

Epidermolysis bullosa

Answer 19

genetic conditions, rare, cause spontaneous blistering of skin + mucus membranes (or after mild trauma
AR versions may be fatal, AD version usually milder

m: avoid minor trauma, treat infections , maintain nutrition (like when oral ulcers), analgesia

Question 20

Collodion baby

Answer 20

a rare type of ichthyosis (inherited itchy skin conditions)

cf: dry scaly skin, born with a taut shiny membrane, risk of dehydration, membrane then fissures + separates within a few weeks leaving either dry thickened skin or normal skin
m: emollients

Question 21

infantile seborrheic dermatitis

Answer 21

this means an eruption of unknown cause in the first 3m

cf: erythematous scaly eruption forming a thick yellow layer (cradle cap), may spread to face/behind ears/flexures/nappy area, not itchy

higher risk of atopic eczema

m: emollients, ointment with sulphur + salicylic acid to wash it off, mild topical corticosteroid if widespread

Question 22

Causes of maculopapular rashes (flat + bumpy)?

Answer 22

• Viral: roseala infantum, slapped cheek syndrome, measles, rubella
• Bacterial: scarlet fever, erythema marginatum, erythema migrans, typhoid fever
• Other: Kawasaki, JIA

Question 23

Roseola infantum

Answer 23

HSV 6/7, usually children<2y

cf: sudden onset high fever (a/w sore throat, coryza, mild diarrhoea), temp reduces then generalised macular/maculopapular rash (mostly on trunk + neck), may get cervical lymphadenopathy

Question 24

Slapped cheek syndrome

Answer 24

aka fifth disease, caused by parvovirus B19, usually school aged children

CF: mild prodrome, then bright red erythema on cheeks (sparing nose + periorbital/perioral areas), then over days/weeks it fades leaving a reticulated lacy pattern

Comps: adult version can cause arthralgia/arthritis (kids usually fine), can predispose aplastic crisis, in fetus can cause hydrops

Question 25

Measles

Answer 25

V contagious virus (RNA paramyxovirus) with 7-10d incubation

cf: prodrome of coryza/sore red eyes/high fever, morbilliform rash (means looks like measles: macules, 2-10mm diameter, may be confluent, generalised + widespread, not itchy, often starts behind ears then to whole body), Koplik spots (blue-white spots in buccal mucosa before rash). starts to fade after about 4d, goes purple-brown colour then goes

IgM antibodies detected within a few days of rash onset

m: supportive, notifiable disease
comps: otitis media (most common), giant cell pneumonia, bacterial pneumonia, tracheitis, febrile convulsions, encephalitis (1-2w after onset), subacute sclerosing pan-encephalitis (v rare may happen 5-10y after illness), febrile convulsions, corneal ulceration/keratoconjunctivitis, diarrhoea, hepatitis, myocarditis

Question 26

Rubella

Answer 26

average lasts 5d

incubation 14-21d, aerosol transmission

cf: erythematous rash, pink-light red macules 2-10mm, often asymptomatic, young children may have mild constitutional sx/coryza, older children/adults can get joint pains/thrombocytopenic purpura. most cases cause pre-auricular + occipital lymphadenopathy, after rash skin may flake, sometimes can get palatal petechiae in prodromal phase

Question 27

Scarlet fever

Answer 27

group A haemolytic strep, aerosol/direct transmission

cf: pharyngitis, headache, high fever, flushed cheeks, bright red strawberry tongue, 12-72h after fever get fine red rough rash, fades after 3-4d then desquamation (peeling)
m: pen V, notifiable disease
comps: rheumatic fever, glomerulonephritis, erythema nodosum

Question 28

What is the skin manifestation of rheumatic fever?

Answer 28

Erythema marginatum

Question 29

Skin manifestation of Lyme disease?

Answer 29

Erythema migrans

Question 30

What bacteria may cause rose spots?

Answer 30

Salmonella typhi (typhoid fever)

Question 31

Kawasaki disease?

Answer 31

CRASH (Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hands and feet) and BURN (fever)

Question 32

Herpes simplex infections

Answer 32

HSV1 - usually enters via MM/skin

may be asymptomatic

CF:

• gingivostomatitis (commonest primary infection): vesicles on lips/gums/anterior tongue/hard palate – painful ulcers, high fever, can last 2w
• skin: cold sores on lip margin (recurrent, may get infected), herpetic whitlow, eczema herpeticum
• CNS: encephalitis, meningitis

Question 33

Chickenpox?

Answer 33

Varicella zoster virus, aerosol + direct transmission, incubation 10-21d

cf: fever, then rash on face/torso/scalp then rest of body (vesicles + erythematous halo then central umbilication + crusting), rash lasts 5-10d. severe cases can affect mucosa (more likely in adults)

m: usually supportive but immunocompromised kids given IV aciclovir/oral valaciclovir
* avoid NSAIDs - increases risk of necrotising fasciitis
* paracetamol for fever/pain
* topical camomile lotion to soothe itch
* sedating e.g. chlorphenamine/non-sedating e.g. loratidine/cetirizine antihistamines

comps: secondary bacterial infection, encephalitis (good prognosis), cerebellitis ~a week after rash causing cerebellar signs for about a month

Question 34

Hand foot + mouth disease?

Answer 34

caused by coxsackie virus or enteroviruses, usually kids <10y

cf: high fever/cough/pharyngitis/stomach ache, oral lesions (red spots – yellow/grey ulcers), then spots on hands + soles that turn into blisters. lasts 7-10d

Question 35

Causes of petechial/purpuric rashes?

Answer 35

• Viral: common for any esp adenovirus + enteroviruses
• Bacterial: meningoccal (80% with meningocci in blood get rash, may initially erythematous/maculopapular), infective endocarditis
• HSP
• Thrombocytopenia
• Vasculitis
• Malaria

Question 36

Impetigo

Answer 36

Localised v contagious staph/strep skin infection

CF: lesions on face/neck/hands, erythematous macules, may become vesicular/pustular/bullous - rupture of vesicles - confluent honey-colour crusted lesions

M: topical Abx for mild e.g. muciporin, systemic Abx for more severe like flucloxacillin (tastes really bad) or co-amoxiclav (tastes better + simpler admin, but broad spec).

Avoid school/nursery until lesions dry (as the fluid is super infectious)

Question 37

Periorbital cellulitis

Answer 37

Fever, erythema, tender + oedema of eyelid/skin near eye
Unilateral
May be from trauma/spread from sinuses/dental abscess

M: IV Abx high dose like ceftriaxone (as posterior spread—orbital cellulitis)

Comp: orbital cellulitis - proptosis, limited movement, reduced visual acuity (may lead to abscess, meningitis, cavernous sinus thrombosis)

Question 38

Boils

Answer 38

Infection of hair follicle or sweat gland with S aureus

M: systemic Abx, surgical drainage sometimes

Question 39

Staphylococcal scalded skin syndrome

Answer 39

Rare but serious, separation of epidermal skin due to an exfoliative staphylococcal toxin

Typically infants/young children

CF: fever + malaise, purulent crusting, tender, localised or widespread. epidermis separates o gentle pressure (Nikolsky skin), skin dries + heals without scarring

M: IV Abx e.g. fluclox + Abx + monitor fluid balance

Question 40

Necrotising fasciitis

Answer 40

Rare severe SC infection - planes from skin down to fascia + muscle, enlarges rapidly - poorly perfused necrotic areas - severe pain + systemic illness

Often S aureus +/- anaerobic

M: debridement + IV Abx

Question 41

Fungal skin infections

Answer 41

ringworm: dermatophyte fungi invade dead keratinous structures like the horny layer of ksin/naisl/hair

tinea capitis: scalp ringworm, causes scaling + patchy alopecia

Question 42

Scabies

Answer 42

mite burrows into epidermis - severe itching
cf: burrows, papule, vesicles; varied distribution (older people finger webs and axillae/around penis or nipples; younger children often on palms/soles/trunk)
M: treat whole household with permethrin cream below neck to all areas and wash off after 8-12h (in babies on face + scalp too obv not eyes)
comps: secondary bacterial infection from scratching (crusted pustular lesions), secondary urticarial/eczematous rash

Question 43

Pediculosis?

Answer 43

headlice

cf: itching scalp/nape, see live lice or nits (empty egg cases, which stay attached as the hair grows)
m: wet combing with fine tooth comb for at least 2d, insecticide shampoos + lotion

Question 44

Psoriasis

Answer 44

Guttate psoriasis commonest in kids - after strep/viral ENT infection

CF: small raindrop/oval erythematous scaly patches over trunk + upper limbs, lasts 3-4m then usually recurs

Chronic psoriasis less common in kids

Question 45

Pityriasis rosea

Answer 45

Acute benign condition, prob viral origin

CF: single round/ovals scaly macule 2-5cm diameter on trunk/upper arm/neck/thigh (Herald patch), then after a few days multiple smaller dull pink macules (follow line of the ribs posteriorly-fir tree pattern)

may itch but no treatment needed and goes in 4-6w

Question 46

Granuloma annulare

Answer 46

Annular lesions with raised flesh-coloured edge (not scaled like ringworm), usually over bony prominences

Usually disappear but may take years

Question 47

Rashes caused by systemic disease?

Answer 47

• facial rash in SLE/dermatomyositis
• purpura in HSP
• erythema nodosum: often no cause, or strep/TB/IBD/drug/sarcoid (rare in kids). tender nodules over legs
• erythema multiforme: target lesions with a central papule surrounded by ertyheamtosu ring. causes: idiopathic, HSV, Mycoplasma pneumonia, drug reaction
• stevens johnson syndrome

Question 48

Causes of nappy rash

Answer 48

• Irritant/contact dermatitis (commonest)
• Candida infection: may cause or complicate it. Erythematous + includes flexures + satellite lesions. M-topical anti fungal
• Atopic eczema
• Rare things like langerhans cell histiocytosis, Wiskott-Aldrich syndrome

Question 49

Features of HSP?

Answer 49

• Prodrome: headache, anorexia, fever
• Rash: usually on legs/buttocks as erythematous macular/urticarial lesions that turn into blanching papule and palpable purpura, usually symmetrical
• Joints: swollen, tender, painful (warmth, effusions + erythema are not characteristics of HSP)
• Sub cut oedema
• Haematuria

Question 50

Verrucae?

Answer 50

These are viral warts of the soles/fingers, caused by HPV

most takes months-years to go, only treat if painful, can try daily salicylic acid paint etc or cryotherapy

Question 51

Acne vulgaris

Answer 51

Can occur before puberty from adrenergic stimulation of sebaceous glands - more sebum - obstructed flow - inflammation

CF: open comedones (blackhead), closed comedones (whitehead), papule, pustules, nodules, cysts, scarring

m: topical to encourage peeling with keratolytic like benzoyl peroxide, topical abx/retinoids, oral abx when >12 with tetracycline/erythromycin, oral isotretinoin for severe in teenagers