Eczema/Dermititus Flashcards
what is hyperkeratosis
increased THICKNESS of KERATIN LAYER
what is parakeratosis
persistence of NUCLEI in keratin layer
what is ancathosis
Increased THICKNESS of EPIDERMIS
what histological signs are seen in an eczema skin biopsy
Oedema between the keratinocytes (spongiosis)
inflammatory cell infiltrate
what is spongiosis
oedema between keratinocytes
what inflammatory cell infiltrate is seen in eczema
acute or chronic with lymphocytes and/pr neutrophils
Acute phase of eczema
papulovescular erythematous lesions oedema ooze scaling crusting
chronic phase of eczema
thickening
elevated plaques
increased scaling
what type of reaction is contact allergic dermatitis
delayed type 4 hypersensitivity reaction
what is the immunopathology of contact allergic dermatitis
langerhand cells in the epidermis pick up antigens
then present the antigens to Th cells in the dermis
Sensitised Th cells travel to the lymph nodes where the antigen presentation is amplified
next time the antigen is there the specified T cells proliferate and infiltrate the epidermis causing contact allergic dermatitis
how do you test for contact allergic dermatitis
PATCH TESTING
put allergens in wells on back
leave wells for 48 hours
remove wells and then check for reaction after 96 hours
What is irritant contact dermatitis
non-specific physical irritation rather than specific allergen reaction to things like soap, detergent, cleaning products, water etc
how does atopic eczema present
pruritus ill defined erythema and scaling generalised dry skin flexural distribution associated with other atopic diseases eg. asthma, allergic rhinitis, food allergy
what are some chronic changes seen with atopic eczema
lichenification (thickened leathery skin) Exorication (repeated picking of skin) Secondary infection -staph aures -herpes simplex
what does a herpes simplex eczema infection look like
monomorphic lesions
what is the diagnosis criteria for atopic eczema
itching plus three or more
- visible flexural rash
- history of flexural rash
- personal history of atopy
- generally dry skin
- onset before 2 years old
treatment for atopic eczema
plenty of emollients avoid irritants including soaps and shower gels topical steroids treat infection phototherapy- UVB immunosuppressants biological agents
what are the other less common types of eczema
drug induced photosensitive lichen simplex stasis dermatitis pompholyx
what is stasis eczema
secondary to:
- hydrostatic pressure
- oedema
- red cell extravasation
what is pompholyx eczema
spongiotic vesicles (intercellular oedema)
what is lichen simplex
localised, well circumscribed area of hyper pigmented thickened skin
