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Flashcards in Eczema Deck (52)
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What % of children will be diagnosed with eczema in their childhood?



How is eczema also known as?

Atopic dermatitis


What % of cases of eczema in children have cleared by the time they reach adulthood?



What are some theories for the increasing prevalence of eczema, particularly in developed countries?

– Social class effect?
– Commoner in cooler climates?
– Pollution? Other environmental factors?

Hygiene hypothesis?


Describe the Modified Hanifin and Rajka criteria for the definition of atopic dermatitis

An itchy skin condition in the last 12 months + 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 relatives if under 4 yo


What gene plays a key role in the pathogenesis of eczema?

Filaggrin gene


What components are involved in the pathogenesis of eczema?

– Many genes implicated
– Key role for Filaggrin gene
– Atopic family history
• Atopic eczema, asthma, allergic rhinitis, food allergy

Epidermal barrier dysfunction

Environmental factors


What 3 processes are involved in the pathology of eczema?

Spongiosis (intercellular oedema) within the epidermis.

Acanthosis (thickening of the epidermis).

Inflammation - Superficial perivascular lymphohistiocytic infiltrate.


What are the clinical features of eczema?

• Distribution
– Flexures, Neck, Eyelids, Face, Hands and feet
– Tends to spare nappy area

Acute changes
– Pruritus, Erythema, Scale, Papules, Vesicles
– Exudate, crusting, excoriation

Chronic changes
– Lichenification, Plaques, Fissuring


List some external/exogenous types of eczema

Contact dermatitis - irritant or allergic

Lichen simplex

Photoallergic or photoaggravated eczema


List some endogenous/internal types of eczema

– Atopic
– Discoid
– Venous
– Seborrhoeic dermatitis
– Pompholyx
– Juvenile plantar dermatitis


What type of eczema does contact dermatitis come under?

Exogenous/external eczema


What type of eczema does lichen simplex come under?

Exogenous/external eczema


What is lichen simplex?

Hyperpigmented, lichenified plaque with accentuated skin lined caused by repeated rubbing of the area. Lichen simplex chronicus (LSC) is a localized, well-circumscribed area of lichenification (thickened skin) resulting from repeated rubbing, itching, and scratching of the skin


What type of eczema does Photoallergic or photoaggravated eczema fall under?

Exogenous/external eczema


What type of eczema does Atopic dermatitis fall under?

Endogenous/internal eczema


What type of eczema does discoid eczema fall under?

Endogenous/internal eczema


What type of eczema does venous eczema fall under?

Endogenous/internal eczema


What type of eczema does Seborrhoeic dermatitis fall under?

Endogenous/internal eczema


What type of eczema does Pompholyx or vesicular eczema full under?

Endogenous/internal eczema


What type of eczema does Juvenile plantar dermatitis fall under?

Endogenous/internal eczema


Describe asteatotic eczema

Asteatotic - diminished or arrested action of the sebaceous glands

Characterized by pruritic, dry, cracked, and polygonally fissured skin with irregular scaling, often on shins of elderly patients


Describe allergic contact dermatitis

Type 4 Hypersensitivity
Delayed hypersensitivity – can take 48-72 hrs to develop reaction

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


What type of reaction is involved in allergic contact dermatitis?

Type 4 Hypersensitivity (delayed)


How long after exposure does allergic contact dermatitis flare?

Delayed hypersensitivity – can take 48-72 hrs to develop reaction


Describe irritant contact dermatitis

Skin injured by:
– Friction – micro-trauma, cumulative
– Environmental factors e.g.Cold, over-exposure to water
chemicals such as acids, alkalis, detergents, solvents


What occupations are at risk of irritant contact dermatitis

– Hairdressers
– NHS staff
– Cleaners


How do we test for allergens?

Patch testing

Potential allergens are applied on the monday and covered
Washed off on wednesday
Examine on friday for results


Describe Seborrhoeic eczema

Symptoms include red, scaly, greasy, itchy, and inflamed skin. Areas of the skin rich in oil-producing glands are often affected including the scalp, face, and chest

In babies, when the scalp is primarily involved, it is called cradle cap.

Dandruff is a milder form of the condition, without associated inflammation


How does Seborrhoeic eczema present in infants?

• Distinctive pattern
• Predilection for scalp (cradle cap), proximal flexures.
• <6months age usually.