why learn about eczema?
- It’s common - 24% of children will be diagnosed with eczema at some point in their childhood
- It’s climbing - Prevalence is rising and Rates of hospital admission for children and adults is increasing
- It’s chronic
- It’s costly
what is eczema also known as?
Also known as atopic dermatitis
what is eczema?
Inflammatory skin condition
where does eczema commonly affect?
Commonly affects flexural areas
is there just one type of eczema?
Multiple types and a spectrum of severity
what type of factors can cause eczema?
Wide range of external (exogenous) or internal (endogenous) factors can induce the condition
what 2 things make up/are going on in eczema?
Barrier dysfunction + inflammation
(picture show triggers involved in eczema)
what is the epidemiology of eczema?
- Overall prevalence is 4% in Western countries
- Most commonly appears in babies and children - By adult life 60% have cleared
- Recent studies indicated rising numbers:
- More so in “developed” regions
- Social class effect?
- Commoner in cooler climates?
- Pollution? Other environmental factors?
is prevelance increasing or decreasing?
increasing
what is the definition of atopic eczema?
An itchy skin condition in the last 12 months
Plus 3 of the following:
- Onset before age 2
- History of flexural involvement
- History of generally dry skin
- History of other atopic disease - History in 1st degree relative if under 4 yrs
what is the pathogenesis of eczema?
• Genetics:
- Many genes implicated
- Key role for Filaggrin gene
- Atopic family history
- atopic eczema, asthma hay fever (allergic rhinitis), food allergy
- Epidermal barrier dysfunction
- Environmental factors
- Immune system dysregulation
what is the pathology of eczema?
- Spongiosis (intercellular oedema) within the epidermis
- Acanthosis (thickening of the epidermis)
- Inflammation - Superficial perivascular lymphohistiocytic infiltrate
what does the epidermis and dermis contain?
Epidermis - outermost layer of skin
Dermis - contains blood vessels, lymph vessels, hair follicles and sweat glands
what is one of the main clinical feautres in eczema?
Itch!!
what does the distribution of eczema tend to be?
Flexures, Neck, Eyelids, Face, Hands and feet
Tends to spare nappy area
what are acute changes seen in eczema?
Pruritus, Erythema, Scale, Papules, Vesicles
Exudate, crusting, excoriation
what are chronic changes seen in eczema?
Lichenification, Plaques, Fissuring
what are other types of exogenous (external) eczema?
• Contact dermatitis:
- Irritant
- Allergic
- Lichen simplex
- Photoallergic or photoaggravated eczema
what are other types of endogenous (internal) eczema?
- Atopic
- Discoid
- Venous
- Seborrhoeic dermatitis
- Pompholyx
- Juvenile plantar dermatitis
• Asteatotic
what type of reaction is allergic contact dermatitis?
- Type 4 Hypersensitivity (T cell mediated)
- Delayed hypersensitivity – can take 48-72 hrs to develop reaction
what happens in allergic contact dermatitis?
- Antigen presenting cells take hapten/allergen to LN and present to naive T cells
- Clonal expansion of these T cells, released into blood stream
- When these T cells next encounter hapten - Mast cell degranulation, vasodilatation and neutrophils
in irritant contact dermatitis, the skin can be innjured by what?
- 1) Friction – micro-trauma, cumulative
- 2) Environmental factors:
- cold
- over-exposure to water
- chemicals such as acids, alkalis, detergents and solvents
Irritant contact dermatitis is a form of contact dermatitis, in which the skin is injured by friction, environmental factors such as cold, over-exposure to water, or chemicals such as acids, alkalis, detergents and solvents
Irritant contact dermatitis may occur in what occupations?
Hairdressers
NHS staff
Cleaners
Dermatitis - under a ring on finger - soaps can accumulate - irritant
Nappy rash
what is patch testing and how is it carried out?
Used in allergic contact dermatitis
- Potential allergens applied (no needles involved!)
- Baseline/standard series – applied to all patients
- Applied Monday
- Remove Wednesday
- Re-assess Friday
