I woke up this morning with a large red blotch on the right side of my chest . There are smaller red blotches on my lower back, arms and thighs. They do not hurt. the tops of my shoulders however are very painful...like I got hit. The only thing I can think of about the blotches is I had shrimp at a restaurant last night. I ve never had a reaction to shrimp or seafood before. I am 56 male, 165 lbs
Hello, Shrimp allergy is likely only of your SY, ptoms started within the hour of eating the food (and also they do not last that long). However, foods like shellfish do have a lot of histamine and can release even more histamine if you are prone for urticaria. You can get a skin prick test for seafood (must be off all antihistamines) and is likely to be negative. What you are having is urticaria, when mast cells on skin release histamine and can be occasionally triggered by histamine-rich foods. See your doctor for a prescription of long-acting antihistamines like fexofenadine 180 mg AM 90,g PM plus/minus cetirizine 10 mg at such time.