When your child breaks out in hives …

With the new schooling year kicking off soon, what do you do when your child breaks out in hives?

Hives are a common skin reaction in children, characterised by a raised, flat pink rash called weals, and is most often caused by allergies. Certain foods can trigger them, as can insect bites or some medication. In winter, some children even develop hives when they are exposed to cold air.

Dr Tamatha Urquhart, a paediatrician from Faerie Glen in Pretoria, who specialises in allergies, and knows all about hives, was asked what causes them and how to treat them.

“Hives can appear anywhere on the body, including the face, lips, tongue, throat or ears,” she said. “They may change shape, move around, disappear and reappear over short periods of time.”

The medical term for hives is ‘urticaria’. When a person is exposed to something that can trigger hives, certain cells in the body release a substance called histamine. This causes fluid to leak from the small blood vessels under the skin. When this fluid collects under the skin, it forms the blotches, which we call hives.

“They vary in size from a few millimetres across to several centimetres and may join together to form larger areas. They can last for hours, or up to one day before fading,” explained Dr Urquhart.

The most common causes are certain foods, medications, or infections. “The most common foods that cause hives are nuts, fish, tomatoes, eggs and dairy products. Certain food additives and preservatives also play a big role,” Dr Urquhart said, adding that it is sometimes difficult to find out exactly why hives have formed.

In terms of classification, urticaria can be classified as acute or chronic, based on the duration of the illness.

“Hives lasting less than six weeks are called acute urticaria. Hives lasting more than six weeks are called chronic urticaria,” Dr Urquhart explained. She went on to say that the cause of chronic urticaria is usually more difficult to identify than the cause of acute urticaria. In fact, for many people with chronic urticaria, the cause is sometimes impossible to determine. “In some cases, the cause may be an autoimmune disease or reaction, chronic infections or food additives and preservatives,” she said.

Another type of urticaria is called physical urticaria – where hives are caused by direct physical stimulation of the skin, for example, cold, heat, sun exposure, vibration, pressure, sweating, and exercise. The hives usually occur right where the skin was stimulated and rarely appear elsewhere.

“It is difficult to determine the exact prevalence of childhood urticaria due to a lack of population-based studies. In my practice, I find acute urticaria to be more common in children than chronic or physical urticaria,” she said.

According to the European Medical Journal, the frequency of urticaria (acute and chronic) in children is about 2,1 to 6,7 per cent.

Hives usually cause itching, but may also burn or sting. While some cases can be mild, urticaria can also be severely debilitating.

According to Dr Urquhart, infection, especially a viral infection, is the most frequently documented cause of acute urticaria in children, and is responsible for up to 40 per cent of cases.

If a child’s hives last for more than a month, Dr Urquhart suggested that you make an appointment to see an allergist, who will take a history and perform a thorough physical exam to determine the cause of your child’s symptoms.

Therapies range from prescription antihistamines and other drugs, such as anti-inflammatory medications and medications that may modify your immune system.

“In some cases, the trigger is obvious – a person eats peanuts or shrimp, and then breaks out within a short time,” she said. Other cases require detective work by the patient, parent and the physician, because there are many possible causes. “In a few cases, the cause cannot be identified,” she said.

Dr Urquhart said that a single episode of hives does not usually call for extensive testing. If a food allergy is suspected, consider keeping track of what your child eats. This will help you discover whether there is a link between what they are eating and when they break out with hives. If the cause of hives can be identified, the best treatment is to avoid the trigger or eliminate it.

In mild cases of hives, your doctor may determine that no treatment is required. However, to make a child less itchy and more comfortable, the doctor might suggest an oral antihistamine. Less often, hives can be a sign of a more serious allergic reaction that can affect breathing and other body functions. In these cases, the person needs immediate medical care.

Antihistamines – available either over the counter or by prescription – are a frequently recommended treatment for hives. “They work by blocking the effect of histamine. Non-sedating antihistamines are preferred. They are effective and long-lasting (and may be taken once a day), are safe and have few side effects”, Dr Urquhart said. In chronic urticaria, antihistamines usually need to be taken daily for at least six months and sometimes up to two years or longer in more severe cases. Serious episodes of urticaria may require more serious treatment regimes.

Furthermore, treatments for allergies that not only inhibit histamine, but also a substance called Platelet-activating factor (PAF), are being recognised as more effective in providing relief for urticaria today. PAF is a molecule which also causes an inflammatory reaction when exposed to an allergen.

Speak to your doctor or pharmacist about a second-generation antihistamine, which is non-drowsy and provides 24-hour relief, and is suitable for children over the age of 12. This treatment, which is available over the counter, is the only antihistamine to have an effect on both histamine and PAF 10.

Go to https://www.gotallergies.co.za for more information about allergies and how to treat them.