Acute urticariais a rash that lasts for any period up to six weeks. It may be due to an allergy. Viral infections are another common cause.
Chronic urticarialasts more than six weeks. Individual spots can last less than 24 hours and occur most days. It affects 1 in 200 children.Chronic urticaria is not associated with severe allergic reactions (anaphylaxis) and adrenaline autoinjector devices are not required. However, it can impact on quality of life by causing difficulty sleeping and problems concentrating at school.
Acute intermittent urticariais the name used to describe a rash that lasts for more than six weeks but just occurs now and again.
Angioedema is swelling, often of the face or lips. Over half of patients with urticaria will also have angioedema. Less frequently angioedema occurs without urticaria.
Chronic urticaria is not an allergy. Some children can have urticaria triggered by cold, heat, sunlight, exercise, scratching, rubbing (see photo of dermographism) and even stress. Often no cause can be found, in which case it is called idiopathic urticaria.
Dermographism is when your skin is very sensitive and will show a red raised rash by rubbing.
Angioedema can be made worse by taking some medicines e.g. ibuprofen, or ACE inhibitorssuch as enalapril. Patients on ACE inhibitors should see their doctor, who may consider changing to an alternative medicine. If your child only gets angioedema but not urticaria, it is important to make sure that these medicines are avoided.
The diagnosis is made on the history and pattern of the rash. Usually no tests are needed.
In a small minority where individual spots last more than 24 hours or there is associated bruising your doctor may consider other medical causes. In this case special tests are required.
When the rash is made worse by specific triggers, these should be avoided. If hot showers bring out the rash, more tepid water should be used for washing.
A regular dose of a non-drowsy antihistamine (for example cetirizine, loratadine) is the treatment of choice. The medicine may need to be taken for many months or even years.
If this does not work then your doctor may increase the dose or add other medicines. Use of steroids for more than a few days is not recommended because of side effects.
The problem may settle after a number of months, but in 3 in 4 children the rash may go on for three years or more.