What causes chronic hives, and is it a food allergy?
In chronic spontaneous urticaria, food is not the cause in most cases, and often no single external trigger is found at all. Not knowing the cause does not mean the condition is not real or cannot be treated. Broad, random testing usually helps less than a good history that looks at how long the lesions last, medicines and associated symptoms, and modern non-drowsy antihistamines are usually the first line.
Key numbers
- Less than 24 hours — A single lesion
- More than 6 weeks — When is it chronic?
- Modern antihistamines — First line
- Emergency — Swelling of the mouth or throat
Do I need comprehensive allergy tests?
In chronic spontaneous urticaria, broad random testing without a history pointing somewhere is not usually recommended. The history decides whether there are drug or physical triggers, infections or signs of another disease. Over-testing can produce positives that have nothing to do with the hives and add confusion.
When is it something else?
The same lesion staying in the same place for more than 24 hours is not the usual pattern of hives, and can open up other diagnoses that deserve assessment.
Treatment sequence
- Modern non-drowsy antihistamines are usually the first line.
- If hives are not controlled, the plan and doses are adjusted under medical supervision.
- Treatments such as omalizumab may be used in chronic urticaria that does not respond.
- Systemic steroids are not a long-term answer for chronic urticaria.
Key takeaways
- Food is not the cause in most cases of chronic spontaneous urticaria.
- Success is measured by the number of days free of hives and itching.
- Swelling of the tongue or throat, or difficulty breathing, is an emergency.
Hives (Urticaria): Causes, Treatment and When It Is an Emergency