eczema Flashcards
how common is eczema in children?
24% of children are diagnosed with eczema at some point in their childhood
is the prevelance of eczema rising or declining?
rising
what is eczema?
inflammatory skin condition
also known as atopic dermatitis
irritated skin
barrier dysfunction and inflammation
where does eczema commonly affect?
flexural areas
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 are the risk factors for eczema?
genetics- many genes implicated
key role for filaggrin gene
epidermal barrie 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 are the contents of the dermis?
contains blood vessels, lymph vessels, hair follicles and sweat glands..
what are the histological changes in acute dermatitis?
Intercellular oedema within the epidermis
Can lead to accumulation of intra-epidermal vesicles
Infiltration of the epidermis with lymphocytes is common
Dermal changes include varying degrees of oedema and a superficial perivascular infiltrate with lymphocytes, histiocytes and occasional neutrophils and eosinophils.
what are the histological changes in chronic dermatitis?
the degree of spongiosis is often mild and difficult to appreciate. Vesiculation is uncommon.
There is significant epidermal acanthosis (thickening of epidermis), which may show a psoriasiform pattern with hyperkeratosis, hypergranulosis and miminal parakeratosis. Fibrosis of the papillary dermis may be present.
what are clinical features of eczema?
itch
distribution- flexures, neck, eyelids, face, hands and feet
acute changes- pruritus, erythema, scale papules, vesicles
chronic changes- Lichenification, Plaques, Fissuring
what are other types of eczema?
exogenous-
contact dermatitis
lichen simplex
photoallergic or photo aggravated eczema
endogenous- Atopic Discoid Venous Seborrhoeic dermatitis Pompholyx Juvenile plantar dermatitis Asteatotic
what is allergic contact dermatitis?
type 4 hypersensitivity
delayed hypersensitivity
what is the pathogenesis of 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
how is the skin injured in irritant contact dermatitis?
friction
environmental factors- cold, over exposure to water
what occupations are likely to get irritant contact dermatitis?
Hairdressers NHS staff Cleaners Dermatitis – under a ring on finger – soaps can accumulate –irritant Nappy rash
when are infants likely to present with seborrhoea dermatitis?
<6months age usually
what is seborrhoeic eczema classed as in adults?
chronic dermatitis
what is increased in the scaly epidermis of dandruff and seborrhehoic dermatitis?
Malassezia yeast
what are the symptoms of seborrhoeic eczema?
Red, sharply marginated lesions covered with greasy looking scales.
Distinctive distribution – areas rich in supply of sebaceous glands (scalp, face, upper trunk).
what is a precursor for seborrhoeic eczema?
dandruff
how do you treat seborrhoeic eczema?
Treat with topical anti-yeast (ketoconazole).
what are the symptoms of discoid eczema?
Circular plaques of eczema.
where is pompholyx/vesicular eczema likely to present?
palms and soles
what are the symptoms of asteatotic eczema?
Very dry skin.
Cracked scaly appearance.
how is asteatotic eczema caused?
Climate – heat
Excessive washing/soaps
what causes venous eczema?
increased venous pressure
what are the symptoms of venous eczema?
increased venous pressure
oedema
what is eczema herpeticum?
Disseminated viral infection
what are symptoms and signs of eczema herpeticum?
Fever and often unwell
Itchy clusters of blisters and erosions
Herpes Simplex 1 and 2
Swollen lymph glands
what are the treatments of eczema?
Patient education
Avoid Causative / exacerbating factors
Emollients (moisturisers) Ointment – greasy but effective Creams – lighter Lotions – more watery Soap substitutes
Intermittent topical steroids
Different potency
hydrocortisone (low)
Betamethasone (potent)
Sometimes need antihistamines or antimicrobials
Calcineurin Inhibitors
Topical Pimecrolimus and Tacrolimus
what are the treatments of severe eczema?
Ultraviolet light.
Immunosuppression. Azathioprine Ciclosporin Mycophenolate mofetil Methotrexate
