EoY4 - General

Question 1

What’s the difference between eczema herpeticum and dermatitis herpetiformis?

Answer 1

Eczema herpeticum
Systemic infection of HSV1 or 2 due to pre-existing condition (commonly eczema)
Features monomorphic mucopurulent/blood filled pustules with central dimpling. Older blisters crust over and heal over 2-6 weeks. May leave scarring if bad.
Can affect multiple organs including eyes, brain, lung + liver. Can cause hepatitis, encephalitis, DIC and, rarely, death.
Diagnose using viral PCR, antibody staining or viral culture.
Manage with oral aciclovir/valaciclovir unless too unwell to tolerate PO meds, then IV antivirals. Watch out for secondary infections - treat with abx.

Dermatitis herpetiformis
Immune response to gliadin fraction in gluten - therefore strongly associated with coeliacs (>90%).
Seen as symmetrical lesions over scalp, shoulder, buttocks, elbows + knees. Lessions appear initially appear as clusters of crusty blisters (due to the intense itching) that lead to hypopigmented scars after resolution.
Can lead to dry skin, nail/hair abnormalitis, aphthous ulcers, ataxia, epilepsy, pericarditis, cardiomyopathy, recurrent miscarriages, NAFLD + NHL
Can diagnose on skin biopsy or IgA blood tests.
Treat by abolishing gluten from diet + consider dapsone (sulfonamide abx), steroids + immunosuppressors

Question 2

What are the common causes of erythema nodosum?

Answer 2

No - idiopathic
D - drugs (NSAIDs + anti-TB)
O - OCP
S - sarcoidosis
U - UC/Crohn's
M - microbes (GABHS, TB, leprosy, etc) + malignancy (lymphoma)

Question 3

What are the common causes of erythema multiforme?

Answer 3

Commonest = HSV (1 > 2)
Infections: mycoplasma, parapoxvirus, HVZ, adenovirus, hepatitis, HIV, CMV + viral vaccines
Drugs: barbituates, NSAIDs, penicillins, sulphonamides, nutrofurantoin, phenothiazines + anticonvulsants

Question 4

What is the Fitzpatrick scale?

Answer 4

Spectrum of skin types graded from 1 to 6 based on how easily an individual burns or tans

Type 1 = always burns + never tans
Type 2 = mostly burns + tans poorly
Type 3 = Tans after initial burn
Type 4 = minimal burn + tans easily
Type 5 = rarely burns + tans dark easily
Type 6 = never burns + always tans darkly

Question 5

For commonly prescribed topical steroids, what is the order of potency?

Answer 5

WEAKEST
Hydrocortisone
Eumovate (clobetasone butyrate)
Betnovate (betamethasone valerate)
Dermovate (clobetasol proprionate)
STRONGEST

Question 6

What is the breslow thickness and what is it used for?

Answer 6

Distance from granular layer to the base of the tumour

Used in malignant melanomas as a strong indicator of prognosis or metastasis risk

Question 7

How do you assess a malignant melanoma?

Answer 7

A = asymmetry
B = border (irregular)
C = colour (more than 2 colours)
D = diameter (>5mm)
E = elevation
F = firm
G = growing