What causes hives in adults?

Updated April 17, 2017

Hives are raised, red, itchy patches of skin. They manifest as large patches as well as rings and have a tendency to rapidly change size. Hives tend to move around and can disappear from one area of your body and reappear in another. Hives can appear on any part of the body and are often caused by allergies. Approximately 15 per cent of the population will get hives at some point. Eighty per cent of people who have chronic hives are idiopathic, meaning there is no apparent cause for their hives. All age groups can be affected by hives outbreaks.

Immune System

Chronic hives can be a sign of problems with the immune system. Autoimmune disorders such as thyroid disease and lupus may be related to chronic hive outbreaks. Have your doctor do the necessary tests for these diseases if your hives are chronic.


Certain foods can trigger hives. Nuts and chocolate have been linked to hives outbreaks, as have citrus fruits and shellfish. If you have a hive outbreak shortly after eating these items, they may be the cause of your hives. Foods that contain additives as well as eggs and wheat may also cause hives in some people. Products made with soy and berries can also contribute to an outbreak of hives.

War Zones

Military personnel in war zones often acquire hives. Stress caused by the war zone situation can cause a person to break out into hives. Exposure to the sun, insects, crowded living conditions, as well as the chafing and sweating that occurs in helmets and other protective gear contribute to outbreaks of hives and other dermatological disorders in war zone areas.

Insect Bites

An allergic reaction to insect bites can cause a hives outbreak. Spider bites can also cause hives. Call 911 if you break out in hives after you are stung by an insect, as hives can be a sign of a severe allergic reaction.


Antihistamines are the most common treatment for hives. Doctors can prescribe this treatment or you can buy an over-the-counter form such as Claritin, benadryl or Zyrtec. Pregnant women should consult their physician before taking an over-the-counter antihistamine. Severe cases of hives are often treated with corticosteroids. When hives become life-threatening, an injection of epinephrine is used to treat the outbreak.

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About the Author

Alexandra Wright is a freelance writer and professional educator. She has taught English as a second language and has experience teaching English at the elementary, secondary and university levels. Wright holds a Master of Arts in English literature.