Eczema Flashcards
Define:
A pruritic papulovesicular skin reaction to exogenous and endogenous agents
Aetiology:
There are lots of different types with lots of different triggers.
The stratum corneum forms a barrier and in eczema there is a defect in this barrier.
Filagrin is a protein important to this barrier function. 10% of those with eczema have a defect in the filagrin gene (they will have hyperlineraity)
Types of exogenous eczema:
Atopic- this is a type 1 hypersensitivity reaction which is usually alongside asthma and allergic rhinitis. In babies the rash tends to be on the face and in children it is mainly in the folds of the skin.
Irritants e.g nappy rash
Contact - type 4 hypersensitivity usually to nickel
Herpecitium - Herpes simplex virus in the eczema . Appear as small ulcerations in the skin
Types of endogenous eczema:
Atopic
Seborrhoeic -due to the overgrowth of yeast starts as dandruff then becomes eczema in the nasolabila folds of the eyebrows, beard, groin and trunk.
Varicose - in association with varicose veins
Pompholyx- a type of eczema that affects the hands and feet, causing tiny itchy blisters vesicles, itching worse at night. FH of atopy.
Lichen
Discoid - dry skin with overwashing in a roughly round pattern
Epidemiology:
Contact - 4%
Atopic - 10-20% of children (will appear in the first year of life)
Symptoms:
Itching Redness Heat Tenderness Weeping Crusting -Ask about irritants -Ask about family history
Signs of acute:
Poorly demarcated
Erythematous
Dry scaling patches
Papules
vesicles
excoriation marks
Signs of chronic:
thickened epidermis
skin lischenification
Fissure
change in pigmentation
What does atopic eczema look like?
Dry, red skin on the inside of flexures
What does seborrhoeic eczema look like?
yellow greasy plaques found in the eyebrows, beard, scalp and parasternal areas
What does discoid eczema look like?
Coin shaped discs on the trunks and legs
What does pompholyx eczema look like?
Vesiculobullous eruption on palms and soles
What does varicose eczema look like?
associated with varicose veins
What does asterotic eczema look like?
dry, crazy paring pattern
Investigations:
usually clinical diagnosis
Atopic - lab testing to see Ig E levels
Contact - 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)
