The reaction (Arrows) shown in Photograph is a which type of hypersensitivity reaction?
A. Type 1.
B. Type 2.
C. Type 3.
D. Type 4.
Ans:A. Type 1.
The reaction shown in the picture above represents wheal-and-flare reaction ,which is a type1 reaction.
Wheal and Flare reaction
- If the antigen is injected beneath the skin—for example, by the sting of an insect or in the course of some medical procedure—the local reaction may be extensive. Called a wheal-and-flare reaction, it includes swelling, produced by the release of serum into the tissues (wheal), and redness of the skin, resulting from the dilation of blood vessels (flare).