hypersensitivties Flashcards
what is a hypersensitivity
immune response that causes collateral damage to self. it is a exaggeration of normal immune mechanisms
what type of hypersensitivity is allergies
type 1
what is a type 1 hypersensitivity
an immune reaction to normally harmless substances in the environment
when does a type 1 hypersensitivity occur
within minutes and up to 2 hrs after exposure
what is an allergen
substance that causes an allergic reaction
describe the role of IgE in type 1 hypersensitivity
IgE is produced and binds to the FcεR1 receptor on mast cells causing degranulation
describe the clinical presentation of type 1 hypersensitivity
urticaria
angioedema
wheezing/asthma
anaphylaxis
what are the investigations for type 1 hypersensitivity
history specific IgE (RAST) skin prick test challenge test serum mast cell tryptase level
when would you do a challenge test
if skin prick test is negative
when would you do a serum mast cell tryptase level
during anaphylaxis
what is the treatment of type 1 hypersensitivity
avoidance
anti-histamines
corticosteroids
epic pen
what is a type 4 hypersensitivity
delayed hypersensitivity
how is type 4 hypersensitivity mediated
TH1 cell mediated
when does type 4 hypersensitivity occur
24-48hrs after exposure
what is an example of type 4 hypersensitivity
contact dermatitis
