Dermatitis Flashcards
what are the different types of dermatitis and what causes them
contact allergic - type IV hypersensitivity
contact irritant - repeated trauma
atopic - genetics + environment
what type of substances cause contact allergic dermatitis
topical therapies
plants
nickel etc
describe the pathogenesis of contact allergic dermatitis
antigen in substance presented to T cell, T cell proliferation, infiltration to the skin causing dermatitis
what investigation is carried out for contact allergic dermatitis and how does it work
patch testing - batteries of allergens applied to the back and left on for 48 hours, after 96 hours they are re-checked looking for dermatitis
how does contact irritant dermatitis differ from allergic dermatitis
non-specific physical reaction rather than an allergy, occurs due to repetitive exposure to substance
list some causes of contact irritant dermatitis
soap
detergent
cleaning products
water/oil
describe the presentation of atopic eczema
ill-defined erythema and scaly across flexural surfaces - wrists and backs of knees
generalised dry skin
atopic eczema is in a triad with which two other diseases
hay fever and asthma
what are the chronic skin changes that arise due to eczema
licenification
excoriation
secondary infection - usually staph
what investigation is carried out for atopic eczema
prick testing - drop of allergen beside marking is placedon the forearm, them skin is pricked to allow allergen into bloodstream to assess if IgE mediated response occurs
what is used to diagnose atopic eczema
itching + 3 or more of flexural rash history of rash atophy dry skin onset before 2 yrs
what is the treatment for eczema
emollients - wet wrap avoid irritants topical steroids, mild initially treat infection phototherapy
