Allergy Flashcards
4 types of hypersensitivity
T1 - IgE med
T2 - Ab = cellular antigen
T3 - Ab = soluble antigen -> immune-complex
T4 - delayed T cell med
3 stages of immunology
1 - sensitisation - exposure -> immune activation -> IgE prod
2 - re-exposure - mmry B cells release IgE ->cross linking on immune cells -> degranulation and mediator release (histamines/prostaglandins)
3 - symptoms - mediators -> smooth muscle spasm, inc cap perm , mucous prod
effect of oral exposure vs skin/resp exposure
oral -> tolerance (Treg cells in gut)
skin/resp -> sensitisation
treatment for anaphylaxis
ABCDE 0.5ml 1:1000 adrenaline O2 and IV fluids 10mg IV chlorphenamine 200mg hydrocortisone ref to allergy clinic
5 inv for allergy
IgE RAST testing - measure serum IgE to specific antigen, no risk anaphylaxis but only shows sensitisation, not clinical allergy
Skin prick testing - allergy pricked under skin
food challenge testing - increasing vol of offending food/drug ingested, gold standard but high risk anaphylaxis
mast cell tryptase - peaks at 1-2 hrs, measure acute anaesthesia
basophil activation test - measures basophil response to allergen IgE crosslinking
interpreting the reesults of skin prick testing
allergen pricked under skin
+ve if wheal >3mm bigger than control
how to prepare for skin prick testing
need to stop antihistamines
what test is use to test for allergy during surgery or while under anaesthesia
mast cell tryptase
Graves - Hypersensitivity
T2
Ab vs TSHR -> hyperT
myaesthenia gravis - hypersensitivity
T2
Ab vs acetylcholine R -> muscle fatigueability
Goodpastures syndro - hypersensitivity
T2
Ab vs basement memb of TIV collagen -> glomeruloneohritis + pulmo haemorrhage
T1DM - hypersensitivity
T4
antigen = panc B cell prot
MS - hypersensitivity
T4
antigen = oligodendrocyte prot (myelin basic prot)
Contact dermatitis - hypersensitivity
T4
antigen = environmental chemicals etc
