What It Is

example of urticaria as seen on a woman's backUrticaria (hives) is a common type of skin rash with raised, skin-coloured to red bumps (welts or wheals) that are usually itchy but can also burn or sting. When a protein called histamine is released, tiny blood vessels (capillaries) leak fluid which accumulates in the skin and causes the rash.

About one in five people will experience urticaria at some time during their lives.

Signs & Symptoms

Urticaria (hives) presents with itchy or burning, skin-coloured to red, swollen bumps. The bumps can coalesce and present as large swollen areas. These bumps or areas have clearly defined borders and are usually smooth and slightly raised. When pressed, the centre of the bumps will turn white. The bumps may last for just a few minutes or some may remain for many hours, then disappear within a day but then reappear elsewhere. After the bumps disappear, the skin usually looks completely normal. Each bump will usually resolve within 24 hours.

Urticaria can be accompanied with swelling under the skin that can sometimes affect the face, lips or throat. This is called angioedema. You should urgently seek emergency medical care if urticaria is accompanied by angioedema and you have trouble swallowing or breathing.

You should see your physician if the symptoms are severe, continue for more than two days, or are accompanied by other symptoms such as fever, joint pain, or night sweats. If you or a family member has urticaria which goes away on its own and does not come back, it is usually not necessary to see a physician.

Urticaria usually lasts six weeks or less and is classified as acute urticaria. In some cases, urticaria can last longer than 6 weeks, even for months or years and is classified as chronic urticaria.


A doctor will diagnose urticaria by asking about symptoms, taking a medical history and doing a physical examination. In some cases, certain tests such as biopsy or blood tests will be performed to check for other medical conditions. If an allergic cause for the urticaria is suspected, a skin prick test may be done to identify the trigger.

Acute urticaria can be caused by infections (including common colds or the flu), or by an allergic reaction to something that is eaten, inhaled, touched or injected. Common agents that can trigger acute urticaria include:

  • Foods such as nuts, eggs and shellfish
  • Drugs such as antibiotics, acetylsalicylic acid (ASA) and ibuprofen
  • Insect bites or stings
  • Latex
  • Pet dander
  • Pollen and some plants
  • Contrast dye

Chronic urticaria (lasting more than 6 weeks) is caused by an autoimmune disorder, when the immune system of the body malfunctions and releases histamine through various mechanisms. An association has been found between urticaria and other autoimmune diseases such as thyroid disease, rheumatoid arthritis, lupus, Sjögren’s syndrome, celiac disease and type 1 diabetes.

Chronic urticaria is more common in adults and in women. It has been estimated that 20 to 30 percent of cases of acute urticaria in infants and young children will develop into chronic urticaria.


Emotional stress is known to precipitate and exacerbate urticaria. Urticaria itself can in turn also be very distressing and impact patients’ quality of life. Some patients break out in hives only when stressed, therefore, keeping stress levels down may be helpful to control the symptoms.

Physical triggers such as exposure to light, heat or cold, vibration, pressure to the skin, sweating and exercise can also cause a form of urticaria called physical urticaria.


Treatment will depend on the severity and cause of the urticaria. In most acute cases, the rash will go away on its own and no treatment is required. If an allergic cause is determined, you will be advised to avoid whatever has triggered the rash.

Showering or bathing in cool water, refraining from scratching, and wearing loose clothing may help relieve symptoms.

Relieving the itching associated with urticaria may involve taking medications.

Antihistamines are taken orally. Antihistamines may be available over-the-counter or may need to be prescribed by a physician. Newer antihistamine drugs that do not make you drowsy or otherwise impaired are preferred. Older types of antihistamines such as diphenhydramine (ex. BenadrylTM ) should be used with caution, particularly in older patients who may be prone to side effects. Urticaria is often treated with larger doses of antihistamines, up to 4 times the label dose. Do not get discouraged: consult your physician if usual doses of over-the-counter antihistamines did not work.

Corticosteroids such as prednisone, also taken orally, are used if symptoms are severe and other treatments do not work. They are used for severe flares and are not recommended for long term use.
People who have severe reactions associated with angioedema should carry a self-injecting epinephrine pen (epinephrine autoinjector) and, if a reaction occurs, use it immediately as prescribed.

Biologics such as omalizumab, a biologic drug known as a monoclonal antibody, is a safe and effective treatment for adolescents and adults who’s chronic urticaria has continued to occur despite other

Some patients with severe disease are treated with other immunosuppressive and immunomodulatory agents such as cyclosporine or hydroxychloroquine. Your doctor will review these treatments if clinically indicated.

Many patients with uncontrolled disease experience a significant impact on quality on life. It is important not to give up as many effective treatments are available. Consult your physician to discuss treatment options.

Take-Home Messages

Urticaria is not contagious. You cannot catch it from somebody who is affected by the condition.

Up to half of urticaria cases have no identified cause. However, there are many treatments that can successfully manage urticaria and provide symptom relief.