Urticaria, or hives, is a skin disorder that causes intense itching and raised red spots or eruptions on the skin. It is very common and about 15-20% of the population will experience a hives outbreak in their lifetime. The length of episodes varies.


Hives may or may not be related to an allergy. There are two types of hives, namely acute urticaria (isolated episode) and chronic urticaria. Acute urticaria is generally the result of an allergic reaction to medication, food or an insect sting. It can last anywhere from a few days to about 6 weeks.

Chronic urticaria can last months. There are many possible causes, all of which are difficult to pinpoint. In fact, in 70 to 80% of cases, the cause is never identified. Among the possible causes:

  • Viral infection or parasite
  • Thyroid disorder (gland located in the neck)
  • Sun exposure
  • Psychological causes such as anxiety and stress
  • Cold water or air (rain, snow)
  • Medication
  • Cosmetic products
  • Histamine-rich foods such as chocolate, shellfish, tuna and strawberries

Persons most at risk

Individuals with a cold, mononucleosis or hepatitis, as well as those with high allergy potential are at a greater risk for developing urticaria.


Urticaria is characterized by the appearance of welts of various sizes on the skin. The site of the red welts can change, just as they can disappear and reappear in the same day. Depending on the cause, other symptoms may also appear. These include:

  • Digestive problems
  • Difficulty swallowing
  • Difficult breathing and asthma
  • Loss of consciousness


Acute urticaria generally occurs within thirty minutes of contact with the sensitizer (food, insect, etc.). In these cases, skin tests are very helpful in confirming an allergy diagnosis.

In order to treat chronic urticaria, the cause must be found. Given that there are countless causes, making a diagnosis is not easy. The physician will begin by making sure that the reaction is not the result of an infection or an underlying disease. Then, in an effort to identify the source of the problem, you will be asked a series of questions (use of medications and exposure to chemical products, changes in dietary habits, changes in personal habits, changes in home or workplace, etc.).


Once the trigger is found, removing it is generally enough. However, the use of an antihistamine (ex. Benadryl®) can help relieve symptoms and, in more severe cases, the physician may prescribe an oral corticosteroid or injectable epinephrine (Epi-Pen®, Twinject®).


Since it can be difficult, and in some cases, impossible to identify the cause of urticaria, prevention is the best treatment. Here are a few simple measures that may help you during an episode:

  • Avoid bathing in water that is too hot
  • Avoid wearing clothes that are too tight and that could rub on the skin
  • Avoid coffee, alcohol and tobacco. Although they are not responsible for triggering episodes, they can aggravate symptoms.

For more information:

Allergy/Asthma Information Association


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