Eczema Flashcards
(19 cards)
What criteria define atopic eczema?
An itchy skin condition in the previous 12 months plus any three of the following:
Onset before age 2
History of flexural involvement
History of generally dry skin
History of atopic disease (or history in 1st degree relatives if under 4yo)
What are the causes of atopic eczema?
Genetics
Epidermal barrier dysfunction
Environmental factors
Immune system dysregulation
Describe the pathological processes associated with atopic eczema?
Spongiosis (intercellular oedema) within the epidermis causes a thickening of the skin with inflammatory involvement
What are the clinical features of atopic eczema?
Itch
Distribution- flexures, neck, eyelids, face, hands and feet. Tends to spare nappy area
Acute changes (pruritis, erythema, scale, papules, vesicles etc)
Chronic changes (lichenification, plaques, fissuring)
What type of hypersensitivity is allergic contact dermatitis?
Type 4 hypersensitivity
Describe the pathophysiology of allergic contact dermatitis
Delayed hypersensitivity- can take up 48-72 hours to develop reaction
Antigen presenting cells take allergen to lymph nodes and present to naive T cells causing clonal expansion of the T cells that are then released into the blood. When these T cells next encounter the allergen they cause mast cell degranulation, vasodilation and increased neutrophils
What causes irritant contact dermatitis?
Skin injury by friction, cumulative micro-trauma or environmental factors (cold, over-exposure to water, exposure to chemicals)
What test should be done in allergic and irritant contact dermatitis?
Patch testing
How does seborrhoeic dermatitis present in infants?
Common on scalp and proximal flexures
Usually <6 months of age
How does seborrhoeic dermatitis present in adults?
Chronic dermatitis
Red, sharply marginated lesions covered with greasy looking scales
Distinctive distribution- scalp, face and upper trunk
Dandruff can be a pre-cursor
What should seborrhoeic dermatitis be treated with?
Topical ketoconazole
What additional test should be done in cases of severe seborrhoeic dermatitis in adults?
HIV testing
What are the characteristics of discoid eczema?
Circular plauqes of eczema
Commonly develops at sites of trauma or infection
What are the characteristics of pompholyx/vesicular eczema?
Present on palms and soles
Intensely itchy
More common in <40’s
Sudden onset of crops of vesicles
What are the characteristics of asteatotic eczema?
Very dry skin with cracked scaly appearance
Most commonly shins affected
Triggers- heat and excessive washing
What are the characteristics of venous eczema?
Increased venous pressure
Oedema
Involvement of lower leg and ankle
What are the characteristics of eczema herpeticum?
Disseminated viral infection Fever and systemically unwell Itchy clusters of blisters and erosions Can occur in HSV1 or HSV2 Swollen lymph glands
Describe the management of eczema
Educate patient
Avoid causative factors
Give emollients (Ointments, creams or lotions whatever is most convenient for patient)
Soap substitutes can be helpful
Intermittent topical steroids
Sometimes need antihistamines or antimicrobials
Calcineurin inhibitors may also be useful
What measures can be taken to manage severe cases of eczema?
UV light
Immunosuppression
