In some people, histamines can cause swelling, itching, and many of the symptoms experienced with hives. As for allergens, hives can be triggered by factors such as pollen, medications, foods, pet dander, and insect bites.
Hives can also be caused by circumstances other than allergies. It is not uncommon for people to experience hives as a result of stress, tight clothing, exercise, illness, or infection. Hives can also develop as a result of excessive exposure to high or low temperatures, or from irritation caused by excessive sweating. Due to the variety of possible triggers, the actual cause of hives often cannot be determined.
Who is at risk?
People with known allergies are more likely to develop hives. You may also be at risk of developing hives if you take medications or are unknowingly exposed to substances you may be allergic to, such as foods or pollen. If you already have an infection or medical condition, you may be more vulnerable to developing hives.
Symptoms of chronic urticaria include:
