Eczema Flashcards
Psoriasis vs eczma
Psoriasis is on extensor surfaces and eczma is on flexure surfaces ususally
what type of disease
Inflammatory skin condition (barrier dysfunction and inflammation)
Diagnostic features of eczma
Itchy skin
+ 2 of:
-before age of 2
-family history (1st degree) onlyif under 4
-history of other atopic disease
-flexure areas
-general dry skin
filaggrin gene
dysfunction leads to barrier dysfunction in the skin. 1 mutation leads to eczma and 2 leads to Ichthyosis vulgaris
hyperlinearity on palms of the hands is a sign of what?
filaggrin gene mutation
Pathology
barrier dysfunction in the epithelium, so more antigens get down to dermis and immune responce to these antigens, can be due to immune dysregulation.
Causes:
-Spongiosis (intercellular oedema) within the epidermis.
-Acanthosis (thickening of the epidermis).
-Inflammation - Superficial perivascular lymphohistiocytic infiltrate.
Clinical features
Itch!!
Distribution:
Flexures, Neck, Eyelids, Face, Hands and feet
Tends to spare nappy area
Acute changes:
Pruritus, Erythema, Scale, Papules, Vesicles
Exudate, crusting, excoriation
Chronic changes:
Lichenification (due to chronic scratching/rubbing), Plaques, Fissuring
increased eye fold name
Dennie-Morgan lines - a sign of atopic eczma in children
External causes
Contact dermatitis (Irritant/allergic)
Lichen simplex (chronic itching/scratching)
Photoallergic or photoaggravated eczema
Allergic contact dermititis
Skin comes into contact with something that causes an allergic reaction
Type of hypersensitivity for allergic contact dermatitis eczma/most other allergies
Eczma = type 4, T helper cells -> mast cells 48-72h
Most other allergies eg peanut = type 1, allergen -> IgE molecule on mast cell -> histamine
allergen vs irritnat
Allergen = immune responce, irritant = skin injury eg friction/environment
Investigation - allergen, type 1 vs type 4
Type 1 eg asthma (IgE) = blood test/skin prick for IgE
Type 4 (Allergic contact dermatitis) = Patch testing
What is Seborrhaeic dermatitis
Associated around hair areas (nose, scalp, ears, upper trunk)
Think Sebum/seaceous glands enter into the hair follicles.
Often not as itchy as other eczema types.
In adults caused by Malassezia yeast (treated with ketoconazole), and might present as dandruff, and have red, sharply marginated lesions covered with greasy looking scales.
Severe Seborrhaeic dermatitis also test for what?
HIV
