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
Where does seborrhoeic dermatitis affect in adults?
Malasseia yeast increased in the scaly epidermis of dandruff and seborrheic dermatitis
Affects areas rich in supply of sebaceous glands
- scalp
- face
- upper trunk
Presentation of seborrheic dermatitis in adults
Red, sharpley marginated lesions covered with greasy looking scales
What can be a precursor for seborrheic eczema?
Dandruff
Progression from dandruff to seborrhoiec eczema
Redness
Irritation
Increased scaling
Treatment of seborrheoic eczema in adults that started with dandruff
Topical anti yeast (ketoconazole)
If have severe seborrheic eczema, what test should be done?
HIV test
What is discoid eczema?
Circular plaques of eczema
Where may discoid eczema develop?
Sites of trauma
Irritation
Where do you get pompholyx/vesicular eczema?
Palms and soles
Who is pompholyx/vesicular eczema common in?
< 40 y/o
Presentation of pompholyx/vesicular eczema
Sudden onset of crops of vesicles
Intensley itchy
What can resolution of pompholyx/vesicular eczema include?
Desquamation
Features of asteatotic eczema
Very dry skin
Cracked scaley appearance
What is most commonly affected in asteatotic eczema?
Shins
Causes of asteatotic eczema
Hot climate
Excessive washing / soaps
Pathology of venous eczema
Stasis eczema or varicose eczema
Increased venous pressure
Oedema
What areas are involved in venous eczema?
Ankle
Lower leg
What can help to treat venous eczema?
Resolution of oedema
- compression stockings
What is eczema herpeticum?
Disseminated viral infection with poorly controlled eczema
Presentation of eczema herpeticum
Itchy clusters of blisters and erosions
Fever
Often unwell
Swollen lymph glands
Causes of eczema herpeticum
Herpes simplex 1 and 2
Treatment of eczema herpeticum
Admission
Anitvirals
Consider secondary bacterial infection
Treatment of eczema
Avoid causative/exacerbating factors Emoillients (moisturisors) Soap substitutes Intermittent topical steroids - hydrocortisone - betamethasone Antihistamines or antimicrobials Calcineurin inhibitors - topical pimecrolimus - tacrolimus
Treatment of severe eczema
UV light Immunosuppression - azathioprine - ciclosporin - methotrexate - mycophenolate mofetil
Two main types of contact dermatitis
Irritant contact dermatitis
Allergic contact dermatitis
What is irritant contact dermatitis due to?
Weak acids or alkalis (e.g. detergents)
Is irritant contact dermatitis common?
Yes
Is irritant contact dermatitis an allergic reaction?
No
Where is contact dermatitis often seen?
Hands
Pathology of allergic contact dermatitis
Type IV hypersensitivity reaction
Name a common cause of contact dermatitis
Cement
