Have itchy, raised bumps on your skin that fade an hour later and then appear elsewhere on your body from time to time? They might be hives—one in five people have it at some point in their lives and one in 20 people have them recurrently.

Dr Lim Chun Siong of DTAP Clinic gives us the lowdown on the the causes of this rash, and the treatment options available.

What causes hives

According to Dr Lim, hives occur when certain cells in the skin release substances that change the diameter and “leakiness” of the blood vessels under the skin. It can result from both allergic reactions and non-allergic causes and the substances released include histamine, which causes itching.

“In an allergic reaction, symptoms other than hives are often present and may include vomiting, diarrhoea, swelling of the eyelids, lips and throat, difficulty breathing, rapid heartbeat, dizziness, and even collapsing in serious cases,” he says.

“However, it can also be caused by non-allergens, including bacterial, viral or parasitic infections, certain medications, alcohol, an underlying autoimmune disorder, heat, cold, pressure, vibration, exercise, and exposure to water.”

He points out that most cases are related to an acute cause such as an infection, medication, or an allergy, and will subside after the underlying cause has been treated.

But in some cases, the rash can persist for months or even years. This condition is known as chronic urticaria and in up to 90 per cent of chronic cases, no cause can be found.

Treatment options

Dr Lim says that treatment usually begins with an avoidance of identified triggers. It is also recommended to avoid aspirin, alcohol, NSAIDs (medications for relief of pain such as ibuprofen), and to avoid wearing tight clothes.

And while H1 antihistamines (such as hydroxyzine, diphenhydramine, chlorpheniramine) are the first line of medications used to relieve symptoms, second-generation H1 antihistamines (such as loratadine, cetirizine and fexofenadine) are often preferred because they have fewer side effects. 

“First-generation H1 antihistamines may be added to the treatment regimen if symptoms are not adequately relieved with second-generation H1 antihistamines. Other medications may be added on top of H1 antihistamines if the symptoms are not adequately controlled, such as H2 antihistamines,” he explains.

“Oral corticosteroids [a class of drug that lowers inflammation in the body] are often reserved for the treatment of severe symptoms or if there are also swelling of the face, lips or eyelids.”

He adds that if a patient’s symptoms still aren’t controlled after going through the above treatment options, they may be treated with medications that suppress the immune system such as cyclosporine or injections with the anti-immunoglobulin E medication omalizumab.