Contact Dermatitis Flashcards
def
allergic or irritant skin reaction due to an external agent
epi
very common
who is more likely to be sensitive to nickel
women (jewellery)
who is more likely to be sensitive to chromate
men (occupational exposure)
what are 3 common causes of allergic contact dermatitis
1 nickel sulfate
2 neomycin
3 myroxylon pereirae
what is neomycin
a topical aminoglycoside antibiotic
what is myroxylon pereirae
AKA as balsam of peru
used in food, drink, perfumes, toiletries for flavouring and fragrance
what are 2 common causes of allergic contact dermatitis in children
1 nickel sulfate
2 gold sodium thiosulfate
what is gold sodium thiosulfate found in
gold jewellery
what are the two forms of contact dermatitis
allergic contact dermatitis
irritant contact dermatitis
what causes irritant contact dermatitis
chronic cumulative ICD by water, soaps, solvents
aetiology of irritant contact dermatitis
direct toxicity without prior sensitization
aetiology of allergic contact dermatitis
delayed hypersensitivity reaction with prior sensitization
risk factors
occupation with frequent exposure to water or irritants
atopic dermatitis
how does frequent water cause ICD
a compromised epidermal barrier allows easier penetration of irritants and allergens
what is phototoxic dermatitis
allergen or irritant is activated by sunlight
history
common to present with occupational Hx of frequent water exposure +/ history of atopic dermatitis
acute onset of (ICD is minutes, ACD is hours) of itchy, red skin which affects hands and face
what symptoms is someone with ICD more likely to present with
burning and stinging skin
what symptoms is someone with ACD more likely to present with
vesicles and bullae (fluid filled sacs on skin)
which hand may be more affected in ICD
the dominant hand
investigations
1 patch testing is gold standard (specific and sensitive)
2 skin biopsy (patch testing)
ICD - variable
ACD - spongiosis, vesiculation, epidermal hyperplasia in chronic ACD
what is spongiosis
intracellular oedema
