Atopic dermatitis & eczema (DERM) Flashcards
Define eczema.
Inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course
What demographic does eczema typically affect?
M=F, usually presents in childhood (most commonly diagnosed before 5 years, affects 10-20% of children)
What do patients with eczema usually have a history of?
Personal or family history of atopic diseases e.g. asthma or allergic rhinitis
How can eczema be described? (2 types)
- acute (flare-up of symptoms)
- chronic (when the patient develops signs of chronic inflammation e.g. lichenification)
What are the typical features of eczema? (4)
- erythema
- scaling
- vesicles
- lichenification in skin flexures
What are the three types of eczema?
- exogenous - irritants (e.g. nappy rash), contact (delayed type IV hypersensitivity reaction to allergen), atopic, skin infections (e.g. S. aureus), food allergens, inhalant allergens (dust mites)
- endogenous - atopic, seborrheic, pompholyx (affects hands and feet), varicose, lichen simplex
- varicose - due to increased venous pressure in lower limbs
What is the genetic basis of eczema?
- genetics –> polygenetic inheritance –> predisposition for increased IgE formation and sensitisation AKA type I hypersensitivity
- filaggrin gene mutations increase risk
- links identified between eczema and areas of genome that encode cytokines and receptors involved in the Th2 mediated immune response
What are some triggers for eczema? (5)
- dust mites
- heat
- humid climate
- stress
- skin irritation
What are some risk factors for eczema? (5)
- filaggrin gene mutation
- age <5 years
- family history of eczema
- allergic rhinitis (hayfever)
- asthma
What is contact dermatitis?
Type of eczema following exposure to a causative agent (Hx may say patient has a new occupation)
What is eczema herpeticum?
- medical emergency where there is severe infection of skin by HSV 1 or 2
- commonly seen in children with atopic eczema and presents as rapidly progressing painful rash with punched out erosions
- potentially life threatening = children admitted for IV acyclovir
What are the signs and symptoms of eczema?
- pruritus (may have excoriations/scratch marks)
- xerosis (dry skin)
- infants - cheeks, forehead, scalp, extensor surfaces (oedematous, prominent weeping and crusting)
- children - flexures especially wrists, ankles and antecubital and popliteal fossae
- chronic eczema often affects the neck, upper back, arms, hands, feet
- acute flares (erythema, scaling, vesicles, papules)
- lichenification (thick leathery skin due to scratching)
- hyperpigmentation if chronic
What are the symptoms of an acute flare of eczema? (4)
- erythema
- scaling
- papules
- vesicles
What are the examination findings for acute eczema?
- poorly demarcated erythematous oedematous dry scaling patches
- papules
- vesicles with exudation and crusting
- excoriation marks
What are the examination findings for chronic eczema?
- thickened epidermis
- skin lichenification
- fissures
- change in pigmentation