Eczema Flashcards
What are the clinical features of eczema?
Erythema Skin dryness Scaling Fissures Vesicles/blisters Lichenification Itch Pain Bleeding Weeping
What is the pathology of acute eczema?
Dermal vessels dilate
Epidermal oedema, separation of keratinocyte ‘spongiosis’
Inflammatory cells invade the dermis and epidermis
(Erythema, vesicles and exudate, oedema of skin)
What is the pathology of subacute eczema?
Less spongosis Epidermal cells malfunction Thickening of epidermis ‘acanthosis’ Increased keratin production Hyperkeratosis & parakeratosis (less vesicles, scaling)
What is the pathology of chronic eczema?
Marked acanthosis, hyperkeratosis & parakeratosis
Persistent vessel dilation & inflammatory cells
(thick, roughed skin, lichenification (dry and acaly fissures) erythema)
What are the types of endogenous eczema?
Atopic Seborrhoeic Asteatotic Gravitational/Varicose Discoid
What are the types of exogenous eczema?
Irritant
Infective
Allergic contact
What is irritant contact dermatitis?
typically involves the dorsum of hands and finger webs
It is a direct result of irritant substances destroying the skin barrier
Hairdressers, chefs, cleaners, nurses
What is allergic contact dermatitis?
Due to a type 4 delayed cell mediated allergic reaction following skin contact with a substance
Nickel in jewellery, hair dye, plants, topical medications, fragrance, occupational
Confirmed by patch testing
How are patch tests carried out?
The test materials are applied to the back under aluminium discs or patches, the occlusion encourages penetration of the allergen
The patches are left in place for 48 h, then after careful marking, are removed the sites are inspected 10 min later, again at 96 h and some-times even later if doubtful reactions require further assessment
test detects type IV delayed hypersensitivity reactions
How are the readings recorded in a patch test?
0 No reaction
± Doubtful reaction (minimal erythema)
+ Weak reaction (erythematous and maybe papular)
++ Strong reaction (erythematous and oedematous or vesicular
+++ Extreme reaction (erythematous and bullous)
What is atopic eczema?
familial predisposition to eczema, asthma and hay fever
Affects 10-20% of children in their lives
Recent discovery of mutations in the fillagrin gene which encodes a skin barrier protein, suggest that the primary problem is a defect in skin barrier function which enables exposure and abnormal stimulation of the immune system
What is discoid eczema (nummular dermatitis)?
seen at any age and in any site
Presents in a disc-like shape with well demarcated nature, discrete plaques
Infection is often a feature of discoid eczema
The cause is poorly understood but it may be a manifestation of atopic eczema
What is varicose eczema?
The lower legs are a frequent site of eczema in the elderly, due to a combination of increased dryness of the skin (termed asteototic eczema), and varicose veins
Varicose eczema occurs around varicose veins with patients often having chronic venous disease
Compression is helpful during the phase of topical treatment, and afterwards, to prevent recurrence
What is aseteatotic eczema?
Common in elderly when the skin fat content decreases ,when the skin surface dries out, a ‘crazy paving’
(eczema craquele) forms
Treat with top steroids initially followed by long-term emollients (aqueous cream/diprobase), avoid excessive washing
What is pompholytic eczema?
provoked by heat or emotional upsets and in people who are allergic to nickel, small amounts of nickel in food
Recurrent bouts of vesicles or larger blisters appear on the palms, fingers and/or the soles of adults
Bouts lasting a few weeks recur at irregular intervals- secondary infection and lymphangitis are a recurrent problem for some patients
Appropriate antibiotics should be given for bacterial infections, aluminium acetate or potassium permanganate soaks followed by applications of a very potent corticosteroid cream, are often helpful
