Eczema (atopic, contact, discoid, dyshidrotic, herpeticum, seborrheic)

Question 1

Definition

Answer 1

A pruritic papulovesicular skin reaction to endogenous and exogenous agents

Question 2

Aetiology/Risk factors

Answer 2

· There are lots of types because there are many different triggers

· Exogenous
o Irritants (e.g. nappy rash)
o Contact (delayed type 4 hypersensitivity reaction to an allergen)
o Atopic

· Endogenous
o Atopic
o Seborrhoeic
o Pompholyx (a type of eczema that affects the hands and feet)
o Varicose
o Lichen simplex

· Varicose - due to increased venous pressure in lower limbs

Question 3

Epidemiology

Answer 3

· Contact - prevalence: 4%

· Atopic - onset in first year of life, childhood incidence: 10-20%

Question 4

Presenting symptoms

Answer 4

· Itching
· Heat
· Tenderness
· Redness
· Weeping
· Crusting
· Ask about occupational exposure to irritants 9eg.. Bleach)
· Ask about personal/family history of atopy (e.g. asthma, hay fever)

Question 5

Signs on physical examination (acute)

Answer 5

o Poorly demarcated erythematous oedematous dry scaling patches

o Papules

o Vesicles with exudation and crusting

o Excoriation marks

Question 6

Signs on physical examination (chronic)

Answer 6

o Thickened epidermis

o Skin lichenification

o Fissures

o Change in pigmentation

Question 7

Signs on physical examination (types)

Answer 7

o Atopic - mainly affects face and flexures

o Seborrhoeic - yellow greasy scales on erythematous plaques. Commonly found on eyebrows, scalp, presternal area

o Pompholyx - vesiculobullous eruption on palms and soles

o Varicose - associated with marked varicose veins

o Nummular - coin shaped, on legs and trunk

o Asteatotic - dry, crazy paring pattern

Question 8

Investigations

Answer 8

· Contact Eczema
o Skin patch testing - a disc containing allergens is diluted and applied on the skin for 48 hrs. It is positive if it causes a red raised lesion

· Atopic Eczema
o Lab testing e.g. IgE levels