Atopic Dermatitis Flashcards
contact dermatitis allergies
poision ivy
nickle
3 classes of atopic dermatitis
1) contact aka allergic dermatitis
2) chronic irritant dermatitis
3) atopic dermatitis
what type of HSR is contact dermatitis
IV
systemic atopic dermatitis induced by cashews/mangos
baboon butt
chronic irritatnt dermatitis
chronic exposure to irritant
burning and stinging (vs itchign in contact)
patch test in irritant
negative (vs + in contact)
atopic dermatitis
genetic disposition to special kind of skin reactivity that usually manifest in childhood
associated with IgE and defective water binding
atopic dermatitis mostly mediated by
Th2
3 phases of atopic dermatitis
acute
subacute
chronic
hot spots for systemic atopic dermatitis
under arm
butt
waste band
10% of atopic dermatitis patients also develop
asthma
two types of defects that lead to atopic derm
defect in immunity
vs defect in barrier
atopic dermatitis people dont do well in
heat!
wet/dry/wet/dry bad
three theories of pathophys
cutaneous (outside in)
immunological (inside out)
neurovascular (pharm)
cutaneous (outside in) theory
inc keratinization
decrease irritant threshold–>ichthyosis vulgaris and increase palmar linearirty
defective water bonding: asteatosis
LOF in fliaggrin gene–>dry skin
sweat retention, loss of antimicrobial peptide
immunological pathophys
increase in Ige production +HSR to some env allergens, but hyposens doesnt work
so impaired t cell mediated
neurovasc theory
increase periph vascular tone–>white demographism
increase in aden cyclase and camp abnormalities may increase release of inflammatory mediators
physical findings of atopic
itching–>scratching–>dermatitis
superimposed bacterial infection is common
skin dry and scaly (esp with air)
facial pallor, cool extremities
dennie’s lines
extra folds of lower eyelids
atopic shiner
hyperpigmentation of lower lips
ichthyosis vulgaris
dry skin secondary to protein defect
changes with age
change from acute gneeralized itchy dermatitis–>itchiness and increased localization (joint flexure, hands, feet)–>thick skin and dry winter skin
aggregavating factors
antigens: food, pollen–>increase IgE
increased sweating
excessive drying of skin (low humidity, bath)
clothing (esp wool) or no clothing (air drying)
infections
hormones
stress
lab findings
70% have delayed blanch rxn with ach injection
moderate peripheral blood eosinophilia
food allergy