Dermatitis Flashcards
what is meant by hyperkeratosis?
increased thickness of the keratin layer
what is meant by parakeratosis?
increased rate of epidermal cell turnover
what is meant by acanthosis?
increased thickness of the epidermis
what is meant by papillomatosis?
irregular epithelial thickening
what is meant by spongiosis?
oedema between keratinocytes
true or false: dermatitis is synonymous with eczema
true
list some features of the acute phase of dermatitis
red lesions
oedema
oozing and crusting
list some features of the chronic phase of dermatitis
thickening
elevated plaques
scaling
what is another name for the thickening of the skin in dermatitis?
lichenification
what symptom is always experienced in eczema?
itch
name the seven types of dermatitis
contact allergic contact irritant atopic drug induced photosensitive lichen simplex stasis dermatitis
what is the basic pathogenesis behind contact allergic dermatitis?
type 4 hypersensitivity
what is the basic pathogenesis behind lichen simplex dermatitis?
physical trauma to the skin such as persistent scratching
list some common causes of contact allergic dermatitis
nickel
latex
plants
what causes weeping in eczema?
oedema between keratinocytes spills out onto the skin surface
what investigation can be used to identify substances causing contact allergic dermatitis?
patch testing
what is involved in patch testing?
wells containing an allergen are applied to skin on the back and left for 2-4 days
which dermatitis - contact allergic or irritant - is a non specific reaction?
contact irritant
list examples of things that can cause contact irritant dermatitis
soap
detergent
oil
nappy rash
true or false: contact allergic and contact irritant dermatitis are easy to distinguish
false
often need to do a patch test
list some symptoms and signs of atopic dermatitis
itch scaling poorly defined erythema dry skin flexural distribution
true or false: atopic dermatitis is associated with other atopic disease
true
what causes secondary infection of atopic eczema?
staph aureus
which virus causes eczema herpeticum?
herpes simplex virus
what does eczema herpeticum look like?
monomorphic
punched out
what is the UK diagnostic criteria for atopic eczema?
itch and at least three of:
flexural rash
history of atopy
dry skin
onset before two y/o
list step up therapy for eczema
emollient and topical steroid
add antibiotics if infected
phototherapy
immunosuppressants if there is systemic upset
what is the most important gene related to atopic eczema?
filaggrin
what is another name for photosensitive dermatitis?
chronic actinic dermatitis
