What are hives?
This is a skin reaction that causes bumps, raised patches, or both to suddenly appear on the skin. The bumps and raised patches are often itchy and may look swollen. The medical name for hives is urticaria.
Are hives contagious?
No, you cannot get hives by touching someone else’s hives or being around someone who has hives.
However, some people develop hives when they have a contagious disease like strep throat or a common cold. If someone with hives has a contagious disease, you can catch the contagious disease — but not hives.
Most hives are intensely itchy. The size of an individual hive ranges from as small as a pinhead to several inches across. Hives can appear alone or in a group. Some hives join together to form large patches called plaques.
Hives come in different shapes and sizes
This patient developed welts that look like small bumps and large patches.
Swelling can be a medical emergency
Along with hives, some people develop swelling deep in their skin or the moist tissue that lines the mouth/lip, eyelids, or other areas. This swelling is called angioedema.
Angioedema is usually harmless; however, it becomes a life-threatening emergency if it causes:
Swelling in your mouth or throat
Angioedema can also cause noticeable swelling on the lips, eyes, and other parts of the body. It usually goes away in a few days. Until the swelling subsides, you may feel uncomfortable.
Swelling can be a medical emergency
If swelling develops in your mouth or throat or you have or difficulty breathing, get immediate medical care or go to the nearest emergency room.
How long do hives last?
Hives are usually harmless and temporary. A single hive tends to last for a few minutes to a few hours. Most hives clear within 24 hours.
As existing hives clear, new ones can form. New hives may appear on the same or different areas on the skin. Most people get new hives for a few days to a few weeks.
If new hives continue to appear for six weeks or longer, you have a condition called chronic hives.
When the cause of chronic hives is unknown, the condition is called chronic spontaneous urticaria (CSU). People who have CSU get new hives daily — or almost daily. This can continue for months or years.
Living with CSU can affect your quality of life. Some people say they feel a loss of control because they never know when hives will appear. Though, hives often worsen during the night. This can make it difficult to sleep.
A continual loss of sleep can make you feel tired and irritable. Some people develop anxiety or depression. All of this can affect your ability to do well in school or at work.
Dermatologists care for people who have chronic hives. Treatment can help relieve the discomfort. If a cause can be found, avoiding the cause can prevent new hives.
For some people, the cause of their hives is something that touches their skin. Your own sweat, cold, sunlight, or the light pressure of a purse strap can cause hives. Dermatologists call this type of hives inducible hives. It only develops when something that causes hives for that person touches the skin.
When this type of hives continues for six weeks or longer, it’s called chronic inducible hives. By avoiding the cause, you can prevent new hives.
Just as hives have many causes, they can also appear on the skin in many ways. You’ll find pictures that show what hives can look like at: Hives: Signs and symptoms.
Related AAD resources
Used with permission of DermNet NZ.
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Wong HK. “Urticaria.” In: Medscape (Elston DM., Ed.) Last updated 9/16/2020. Last accessed 8/1/2021.
Yosipovitch G and Kwatra SG. “Chronic urticaria.” In: Living with itch: A patient’s guide. The Johns Hopkins University Press. United States, 2013: 56-9.
Paula Ludmann, MS
Rajiv Nijhawan, MD, FAAD
Dara Spearman, MD, FAAD
Last updated: 9/28/21