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I always get confused with this. Dont u get rash and itching in both type 1 and 4 hypersensitivity ? How do u differentiate between the both
SKin rash and Itching - Type 1 or 4 hypersensitivity ?
- Thread starter Kobebucsfan
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Below is a great chart from http://www.microbiologybook.org/ghaffar/hyper00.htm
They describe type I reactions as "Weal and flare" [i.e. hives] and type 4 as "erythema and induration". Both can be itchy, but a type I will be more widespread and urticarial in nature whereas a type 4 rash will be more localized and can be associated with blistering, swelling and redness.
IMO the best way to distinguish these on a test would be from history, specifically what the inciting antigen was and the time course of the reaction was (type 1 is immediate and type 4 is delayed reaction).
They describe type I reactions as "Weal and flare" [i.e. hives] and type 4 as "erythema and induration". Both can be itchy, but a type I will be more widespread and urticarial in nature whereas a type 4 rash will be more localized and can be associated with blistering, swelling and redness.
IMO the best way to distinguish these on a test would be from history, specifically what the inciting antigen was and the time course of the reaction was (type 1 is immediate and type 4 is delayed reaction).
