Burning or itchy welts begin to develop in your throat. You may be at risk of suffocation.
You develop hives accompanied by dry throat, cough, cold sweats, nausea, dizziness, difficult breathing, or a sharp drop in blood pressure after an exposure to such things as a bee sting or insect bite or a new medication. This may be a severe allergic reaction known as anaphylaxis.
You have recurring bouts of hives lasting a month or more. You may have a chronic condition that needs professional treatment.
You develop symptoms of angioedema, particularly in the head and neck. This requires medical attention before the condition spreads to the throat or tongue and blocks the air passage to the lungs.
You develop hives after a blood transfusion. You may be having an allergic reaction to donor blood.
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