Hives (Urticaria)

Hives (the common term for urticaria), are pink or red itchy rashes, that may appear as blotches or raised red lumps (wheals), on the skin. They range from the size of a pinhead to that of a dinner plate. When hives first start to appear, they can be mistaken for mosquito bites. Swellings usually disappear within minutes to hours in one spot, but may come and go for days or weeks at a time, sometimes longer. In most cases hives are not due to allergy and they can be effectively treated with a non-drowsy antihistamine. When hives occur most days for more than six weeks this is defined as chronic (ongoing) urticaria, which may require additional medication. 

pdfASCIA PCC Urticaria (Hives) 2019130.88 KB

Hives occur in the skin and are common

Up to 20% of people will develop hives at some time during their life. In most cases, hives are not due to allergy. Underneath the lining of the skin and other body organs (including the stomach, lungs, nose and eyes) are mast cells. Mast cells contain chemicals including histamine. When these are released into the skin they irritate nerve endings to cause local itch and irritation and make local blood vessels expand and leak fluid, triggering redness and swelling.

Can hives occur anywhere else?

Hives can also cause deeper swellings in the skin and mucosa, this is called angioedema. These swellings are often bigger, last longer, may itch less, sometimes hurt or burn and respond less well to antihistamines. Large swellings over joints, for example, can cause pain that feels like arthritis, even if the joint is not involved. Angioedema most frequently affects the face and lips. Although hives and facial swelling can be uncomfortable and cosmetically embarrassing, they are not usually dangerous. Information on angioedema is available on the ASCIA website.

Hives are rarely due to a serious underlying disease

Whilst a clear cause of hives in not obvious in many cases, causes may include:

An allergic cause for hives should be suspected if episodes are rare, short-lived and occur under specific circumstances, for example:

Ongoing hives lasting days at a time are almost never allergic in origin, with the exception of some cases of allergy to medicines. Stress is a very rarely the cause of hives but may make the symptoms worse. 

In some people hives are caused by physical triggers, including cold (such as cold air, water or ice), heat, sunlight (solar), vibration, rubbing or scratching of the skin (dermatographism), and delayed pressure (such as after carrying heavy bags.  In other people, exercise (sweating), stress, alcohol, spicy food or coffee may cause symptoms.

Chronic urticaria is defined when hives occur most days for more than six weeks

Symptoms of chronic urticaria usually resolve, although this can take months or several years. Most people with chronic urticaria manage with appropriate doses of non-drowsy antihistamines. People with severe symptoms interfering with quality of life may be referred to a clinical immunology/allergy specialist or dermatologist for assessment and consideration of additional medications.

Most people with hives do not need tests

Tests are sometimes done when hives go on for long periods, or when unusual symptoms are occurring around the same time. This is to exclude other diseases, which may appear as hives first, and other conditions later. If hives are associated with high fever, bruising, bleeding into the skin, purple lumps that last for several days, or sore joints, a doctor’s appointment should be arranged promptly.

Allergy testing is performed when the history suggests an allergic cause. 

Treatment of hives 

Whilst most hives resolve within a couple of weeks without any specific treatment, the following treatments may be useful:

For patient support organisations go to www.allergy.org.au/patients/patient-support-organisations

© ASCIA 2019

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ASCIA resources are based on published literature and expert review, however, they are not intended to replace medical advice. The content of ASCIA resources is not influenced by any commercial organisations.

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Updated May 2019