Whether you call them welps, welts, bumps, hives, or the medical term urticaria, all mean an itchy rash that can leave you asking yourself what kind of new allergy you’ve developed. The hallmark of urticarial are wheals that each last less than twenty-four hours and leave behind normal skin when they resolve. You may be racking your brain to figure out why you have the hives. Unfortunately, it is unusual to identify a cause.
Hives can be from food allergy, drug allergy, viruses, or can be idiopathic meaning there is no known cause. Food allergy hives typically occur within two hours of eating and resolve within a few hours of treatment. Hives from food allergy usually do not last for days. Once hives continue for more than a day or two, other causes are considered. It is important to seek emergency care if the hives occur within two hours of eating or if there are any other symptoms such as cough, wheeze, or vomiting. If you are otherwise well and the hives last for weeks, the cause is unlikely to be food allergy.
Medications can cause hives as a side effect or as part of a more acute allergic reaction. Hives can occur the first time you take a medication or after years of taking a medication. There is no testing available for most medications and so it can be difficult to determine if a specific medication is a cause. We always consider the medication history when evaluating patients with hives.
Interestingly, detergents, soaps and other common household items usually have nothing to do with hives. Scented agents can worsen eczema, a different type of rash, but are extremely unlikely to cause hives. Changing to hypoallergenic personal care items can help some rashes, but not urticaria.
Viruses can cause hives. Sometimes a patient has cold symptoms that suggest a viral cause, but not always. We discuss all your symptoms carefully to determine if there is an underlying cause. Most hives from viruses last for a few weeks and resolve. For a subset of patients, hives last longer than 6 weeks.
Once hives last longer than 6 weeks, they are termed chronic spontaneous urticaria. Idiopathic hives, also called spontaneous hives, are hives for which there is no known cause. The focus is on treatment of symptoms. If antihistamines are not helpful, a medication called Xolair can be prescribed by your allergist.
Don’t suffer with hives! Though we may not be able to identify the cause, together we will find a treatment plan that lets you get back to your life.
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