New treatment can help people with peanut allergies to build tolerance

Four children who would once have suffered an allergic reaction from consuming a single peanut can now eat a handful each day after taking part in a pioneering medical study.

The children, aged eight to 12, were injected once or twice per month with omalizumab - an antibody used to reduce allergic reactions - for the first 18 weeks of the six-month study by the Hong Kong Sanatorium and Hospital's allergy centre.

From the 12th week of the study, peanuts were gradually introduced into the children's diets. The amount was increased every two weeks, and by the end of the study, the children were eating nine peanuts per day without ill-effects where once they would have suffered rashes, swollen tongues and vomiting from less than one nut.

In controlled tests, children could eat up to 20 nuts without any reaction.

"The result is very encouraging because patients will no longer need to worry about allergic problems from any accidental exposure," said Dr Lee Tak-hong, director of the centre.

Accidental exposure - such as when people with a nut allergy eat food that is not labelled as containing nuts - accounts for about half of the allergic reactions treated by medics. In severe cases, an allergic reaction can cause the victim to stop breathing or lead to a drop in blood pressure that can be fatal.

Unlike other allergies, a peanut allergy rarely disappears and there is no drug to cure it, said June Chan King-chi, senior dietician at the centre.