Type 4 hypersensitivity reaction Flashcards
1
Q
Type IV hypersensitivity
A
Delayed reaction
Onset typically after 24-48 hours
2
Q
Pathophysiology
A
T cell mediated
Generation of specific T cells and memory T cells
3
Q
Examples
A
Contact dermatitis Graft rejection Psoriasis Poison ivy Diabetes Sarcoidosis TB
4
Q
Direct skin contact allergens
A
Preservatives within cosmetics
5
Q
Airborne contact allergens
A
Fragrance, plants
6
Q
Injections allergens
A
Tattoo
7
Q
Clinical presentation
A
Very distinctive rash pattern
Think about where the external antigen is on the body e.g. an elastoplast
8
Q
Investigations
A
Patch test - gold standard, allergens placed on patients back for 48 hours. Readings done at 48 hours and 96 hours.
9
Q
Management
A
Allergen avoidance Emollients Topical steroids UV phototherapy Immunosuppressants
