What are hives?

Hives — also referred to as urticaria — are welts on the skin caused by an itchy rash. Hives can appear on any part of the body and are often triggered by an allergic reaction.

Hives aren’t contagious, meaning you won’t develop them on your skin by touching hives on another person. However, the trigger that causes this skin reaction can be contagious.

Some causes of hives that are contagious are:

Although allergies can trigger hives, other things can also lead to hives. Understanding the cause can help to address ways to prevent this reaction and avoid the spread of hives.

Allergic hives

Contact with an allergen is the most common cause of hives. Allergic hives aren’t contagious.

Common allergens that can trigger hives are:

Infection-induced hives

Some bacterial and fungal infections can cause hives. Examples of these conditions include:

These types of hives themselves aren’t contagious, but if the condition that causes them spreads, you too could develop hives if you develop the condition.

These infections can spread through:

  • airborne germs from sneezing and coughing
  • poor hygiene
  • sharing eating utensils
  • direct contact with saliva of an infected person
  • contact with stool

You’re at more risk of developing an infection and getting hives if you:

Physical hives

Overexposure to the sun, cold, or water can cause physical hives. Body heat from physical activity can also cause a reaction.

Chronic hives

If you have chronic hives — or chronic urticaria — welts appear for up to six weeks at a time. In more severe cases, chronic hives can last for years.

Hives typically go away within 48 hours, unless you’ve developed a chronic case of urticaria. Chronic urticaria can last or recur for up to six weeks at a time. Find out 15 ways to get rid of hives.

You should seek immediate medical attention if in addition to hives you experience:

Through lifestyle changes and precautions, you can help to prevent hive reactions.

If you have a known allergy, you can do the following to prevent hives:

  • Avoid foods you are allergic to.
  • Carry an EpiPen in case of allergic emergencies.
  • Find alternatives to medication or prescriptions that contain allergens.

Contagious bacteria can also cause conditions that trigger hives. Here are a few tips you can try to prevent becoming infected with this bacteria: