What is urticaria?
Urticaria is a common condition of the skin that affects about 1 in 6 people at some stage in their lives. People with urticaria describe itch and red, itchy lumps on their skin or swelling. Urticaria is an itchy skin rash. It often looks like hives or itchy bites, similar to mosquito bites. Sometimes the skin rash of urticaria can result in very large itchy patches. The itchy lumps of urticaria can last for hours or for up to a day. The rash of urticaria is due to inflammation in the surface layers of the skin which leaves itching and swelling. Whilst urticaria is alarming in appearance it is not life-threatening or dangerous.
About 1:10 people who have urticaria can also have angioedema, that is deeper tissue swelling, which can affect any area of skin, such as the palms or soles of the feet, the arms or legs, the face or the lips, tongue or throat. The only time when angioedema is dangerous is where swelling of the throat occurs causing shortness of breath or constriction of the throat is a more concerning feature of angioedema and should be taken seriously when this occurs.
Why do people have urticaria?
Except for urticaria accompanying acute allergic reactions, the cause of urticaria is usually not known. Common causes of urticaria are listed below: 1) Acute allergic reactions
People who suffer from allergic reactions to food, insect stings or drugs can have urticaria as part of an allergic reaction. In this case the urticaria usually comes on within minutes of being exposed to the allergic trigger and only occurs on exposure to the trigger.2) Acute urticaria
Sometimes urticaria can start for no particular reason, often after an infection. In this case the urticarial rash and/or angioedema occurs often usually every day, but usually goes away in less than 6 weeks. Because acute urticaria usually gets better on its own, it is not usually worthwhile seeking a specialist opinion for daily urticaria that lasts less than 6 weeks.3) Chronic urticaria
Chronic urticaria is where the rash of urticaria occurs on a daily, or near daily basis for more than 6 weeks. Whilst people who suffer from acute urticaria usually recover in 6 weeks or less, about 1:10 people have daily rashes that persist for greater than 6 weeks: known as chronic urticaria. Nine out of ten people with chronic urticaria for greater than 6 weeks will be better in 12 months. However some people suffer from very long-lasting urticaria, which can continue over many years. Some people who have the rash for more than 12 months will still suffer from urticaria in 10 years.4) Physical Urticaria
In some cases of chronic urticaria there is a very evident trigger, such as heat, cold, pressure or exercise. In this case the urticaria is known as “physical urticaria”.
Why do people get urticaria?
Urticaria and angioedema are due to histamine and other allergic substances being released in the skin. With the exception of urticaria in association a severe allergic reaction, the reason why urticaria occurs is not known. Some studies have shown that in urticaria there is an abnormal immune response to histamine-containing cells in the skin making them more likely to release their contents, but the exact details of these are not established. Urticaria on a daily basis is almost never due to an allergy, therefore allergy tests are usually not helpful.
How is urticaria treated?
Since urticaria usually goes away on its own, the focus of treatment is to control the symptoms until it gets better, which it will in most instances. Since urticaria is also not a life-threatening condition, its important that medication taken does not have serious side-effects.
The most proven effective treatment for urticaria is antihistamines. Non-sedating antihistamines can be taken on a daily basis and can be used to prevent the rash in many instances.
Other factors to take into account are to find out what drugs a person is taking as often aspirin and drugs such as beta-blockers can cause or exacerbate urticaria and should usually be ceased in those who suffer from it.
What do I do if anthistamines don’t work?
If antihistamines are not effective for urticaria, then it is necessary to see your doctor and often a specialist. Since chronic urticaria is often a very long-lasting condition, and one that is not associated with severe health effects, steroid treatments are best avoided, especially in the long term.
Sometimes the older-fashioned sedating antihistamines can be used effectively for urticaria, especially when taken at night.
Dietary strategies, especially reduction in food chemicals in the diet may also assist, especially in those people who notice that some classes of food can cause their rash. Dietary modification of this nature is best done in consultation with a dietitian who has specific expertise in allergies and some studies suggest effectiveness.
A new drug, omalizumab, has recently been shown to be very effective in chronic urticaria. It is administered by injection on a monthly or fortnightly basis. This drug has been in use in Australia for asthma for some time and is now available under strict criteria for PBS subsidised use in severe cases of chronic urticaria.
Other treatment strategies that can be tried are anti-inflammatory drugs such as hydroxychloroquine or other anti-rheumatic drugs, although there is little evidence other than clinical experience to support the use of such drugs.
More informationPatient information:
Australasian Society of Clinical Immunology and Allergy (ASCIA) - UrticariaMedical information:
Both these articles are available free in full PDF format by clicking through the WILEY Online Library which can be accessed through the PubMed links below.EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria.
Zuberbier T et al.Allergy. 2009 Oct;64(10):1427-43. doi: 10.1111/j.1398-9995.2009.02178.x.EAACI/GA(2)LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria.
Zuberbier T et al. Allergy. 2009 Oct;64(10):1417-26. doi: 10.1111/j.1398-9995.2009.02179.x