Hives are often caused when the body releases a chemical called histamine. Histamine is released during an allergic reaction. Many people, though, get hives without being exposed to something they are allergic to.

Things that may cause hives are:

  • Food allergies or reactions, most commonly:
    • Milk
    • Eggs
    • Nuts
    • Fish or shellfish
    • Wheat or soy
  • Medicines
  • Insect bites or stings
  • Latex
  • Pressure, cold, heat, or sun
  • Stress
  • Certain health problems, such as:
    • Viral infections, such as HIV infection, hepatitis, and cytomegalovirus
    • Immune system problems
    • Vasculitis (inflamed blood vessels)
    • Thyroid disease—hypothyroidism or hyperthyroidism
    • Some cancers, such as lymphoma
    • Diabetes Type 1

Risk Factors

Things that may raise the risk of hives are:

  • Being exposed to an allergen—something that causes an allergic reaction
  • Being exposed to something that triggered hives in the past



Symptoms of hives can vary from mild to severe. They may include:

  • Itchiness, redness, and swelling
  • Excessive swelling of the eyelids, lips, or genitals
  • Burning or stinging
  • Problems breathing or swallowing


The doctor will ask about symptoms and past health. A physical exam will be done. The person may be referred to a doctor who treats skin disorders or allergies.

Tests may be done, such as:

  • Blood tests
  • Skin prick test—to check for allergies
  • Skin biopsy



The goal is to find and avoid the cause of hives.

Medicines may help to ease symptoms and manage the cause. They may be applied to the skin or taken as a pill. They may include:

  • Antihistamines
  • Leukotriene antagonists
  • Steroids
  • Anti-inflammatory medicines
  • Medicines to treat the immune system

Other treatments may include:


The best way to prevent hives is to avoid allergens that caused hives in the past.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.