Dermatitis and Eczema Flashcards
in cornification where is the nucleus lost from cells
at the granular layer
what is seen histologically in eczema
spongiosis (oedema between keratinocytes)
inflammatory cell infiltrate (acute or chronic; lymphocytes and/or neutrophils)
what is a common symptom in ALL types of eczema
itching
what is eczema a form of
dermatitis
describe the acute phase of eczema
papulovesicular erthematous (red) lesion, oedema (spongiosis), ooze or scaling and crusting
describe the chronic phase of eczema
thickening (lichenification), elevated plaques, increased scaling
what are the key words to remember for the presentation of eczema
itchy, ill defined, erythematous and scaley
what is seen histologically in ALL types of dermatitis
spongiotic dermatitis
what causes contact irritant dermatitis
trauma (eg soap, water)
what causes atopic dermatitis
genetic and environmental factors resulting in inflammation
what causes lichen simplex dermatitis
physical trauma to skin (e.g. scratching)
what causes stasis dermatitis
physical trauma to skin (hydrostatic pressure - peripheral oedema)
what extra feature is seen histologically in drug related dermatitis
eosinophils
what extra feature is seen histologically in lichen simplex dermatitis
external trauma
what extra feature is seen histologically in stasis dermatitis
extravasation of RBS’c (leakage into surrounding tissue)
what are common causes of contact allergic dermatitis
nickle, chemicals, topical therapies, plants
why can weeping occur in eczema
due to acute oedema of the skin, liquid weeps out
what is the difference between a vesicle and a bullae
vesicle- small
bullae-big
describe the immunopathology of contact allergic dermatitis
langerhans cells in epidermis processes antigen (increased immunogenicity) anf present it to Th cells in the dermis.
sensitised Th cells migrate into lymphatics and then to regional nodes where antigen presentation is amplified
on subsequent antigen challenge, sensitised T cells proliferate and migrate to infiltrate skin = dermatitis
how long are skin patch batteries left in place and when are the reactions checked
left for 48 hours
checked after 96 hours
what is the difference between irritant contact dermatitis and contact allergic dermatitis
irritant contact dermatitis is a non specific physical irritation rather than a specific allergic reaction
what are features commonly seen in contact irritant dermatitis
erythema, scaling, fissuring, lichenification, nail dystrophy, crusting, erosions
is nappy rash irritant or allergic contact dermatitis- how can you tell
irritant- to urine, as flexures usually spared
what is and causes ‘lip-lick’ chilitis
lip irritant contact dermatitis to saliva
what is the difference between atopic eczema and atopic dermatitis
none same thing
why does atopic eczema have such a big impact on childrens QOL
pruritus= sleep disturbance= neurocognitive impairment
affects whole family
what mutation is associated with atopic eczema
filaggrin mutation
what is seen on the palms of chldren with atopic eczema
extra linear palm
what ‘cycle’ is seen in eczema
the itch- scratch cycle
how does atopic eczema present
pruritus, ill-defined erythema and scaling, generalised dry skin, flexural distrubution
what atopic diseases is atopic eczema associated with
asthma, allergic rhinitis (hay fever), food allergy,
what ONLY happens in ATOPIC eczema
eczema beneath the earlobe- is pathognomonic
how does eczema present in darker skin
papules, erythema (harder to see), extensive lichenification, prurigo-like nodules, hypertrophic scarring and keloid formation
what are the chronic changes of atopic eczema
lichenification
excoriation
secondary infection
what does (gold) crusting of eczema mean
secondary staph aureus infection
what is eczema herpeticum
when eczema becomes infected with herpes simplex virus- systemic and potentially life threatening
describe the presentation of eczema herpeticum
extremely painful, monomorphic punched out lesions
how do you treat eczema herpeticum
anti viral e.g. acyclovir
the uk diagnostic criteria for atopic eczema; WHAT plus 3 or more;
ITCHING + 3 or more;
- visible flexural* rash
- history of flexural* rash
- (cheeks and extensor in infants)
- personal history of atrophy (or 1st degree relative if <4yo)
- generally dry skin
- onset before age of 2
how do you treat eczema
- lots of emollients
- avoid irritants including shower gels and soaps
- topical steroids
- treat infection
- phototherapy (mainly UVB)
- systemic immunosuppressants (cyclosporin, methotrexate, azathioprine)
- biologic agents
what is the most important gene in skin barrier function
filaggrin
what causes eczema
multifactoral; genes + environment + immunology
describe discoid eczema
coin shaped lesions, patients often atopic too
what is chronic actinic dermatitis
photosensitive eczema
how does photosensitive eczema present
extensive lichenification and chronic erythema- cut off at collar
what is the presentation of stasis eczema
eczema follows varicose veins
how do you treat stasis eczema
treat hydrostatic pressure- compression stocking, surgery etc
what is cradle cap
seborrhoeic dermatitis- can be atopic eczema often with co fungal or yeast infection
what is pompholyx eczema
eczema where vesicles appear due to rapid onset of intercellular oedema
what is lichen simplex
when normal skin has become thickened and scaley due to scratching
how is lichen simplex treated
potent topical steroids
