Eczema Flashcards
Another name for eczema
Atopic dermatitis
What kind of condition is eczema?
An inflammatory skin condition
Where does eczema commonly effect?
Flexural areas
Definition of atopic eczema (criteria)
An itchy skin condition in the last 12 months PLUS 3 of the following
- onset before age 2
- history of flexural involvement
- history of general dry skin
- history of other atopic disease
- history in 1st degree relative if under 4 years
What is asked about in an atopic family history?
Atopic eczema
Asthma
Hay fever (allergic rhinitis)
Food allergy
Pathology of eczema
Spongiosis (intracellular oedema) within the epidermis
Acanthosis (thickening of the epidermis)
Inflammation - superficial perivascular lymphohistiocytic infiltrate
Accumulation of intra epidermal vesicles
Pathology of chronic spongiotic dermatitis
Vesiculation uncommon
Significant epidermal acanthosis - which may show psoriasiform pattern with hyperkeratosis, hypergranulosis and minimal parakeratosis
Fibrosis of papillary dermis may be present
What is epidermal acanthosis?
Thickening of epidermis
Presentation of eczema
ITCHY Erythema Scale Papules Vesicles Exudate Crusting Excoriation
Distribution of eczema
Flexures Neck Eyelids Face Hands Feet
Where does eczema tend to spare?
Nappy area
Chronic changes of eczema
Lichenification
Plaques
Fissuring
Types of eczema
Chronic Atopic Contact dermatitis Lichen simplex Photoallergic or photoaggravated eczema Discoid Venous Serborrhoeic dermatitis Pompholyx Juvenile plantar dermatitis Asteatotic
Pathology of allergic contact dermatitis
Type 4 hypersensitivity
Delayed hypersensitivity
Antigen presenting cells take hapten / allergen to LN and present to naïve T cells
Clonal expansion of these T cells, released into blood stream
When these T cells next encounter hapten
Mast cell degranulation, vasodilation and neurophils
How long can allergic contact dermatitis take to develop a reaction?
48 - 72 hours
What is irritant contact dermatitis?
A form of contact dermatitis, in which the skin is injured by friction and environmental factors
How is skin injured in irritant contact dermatitis?
Friction - micro trauma - cumulative Environmental factors - cold - over exposure to water - chemicals such as acids, alkalis, detergents and solvents
What occupations tend to get irritant contact dermatitis?
Hairdressers
NHS staff
Cleaners
Who gets seborrheic eczema?
Infants < 6 months
Adults with chronic dermatitis
Where does seborrheic dermatitis affect in infants?
Scalp
Proximal flexures