Welcome to healthcare magic.
Yes what you are having is an uncommon type of urticaria
called cholinergic urticaria. It comes under group of diseases called physical urticarias. As your body temperature increases with exercise or brisk walking or running this releases histamine
from your sensitive allergy
producing cells under your skin called mast cells. Kindly consult a dermatologist
for complete work up and treatment.
Hope this helped.
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