Key Point:

Due to an increased risk of anaphylaxis, all children with cold urticaria and their parents should be counseled regarding anaphylaxis risk and provided with an epinephrine autoinjector.

BOSTON—Cold urticaria—that is, urticaria and angioedema developing after exposure to the cold—is a rare condition in children. When it does occur, however, it is a harbinger of danger: Children with cold urticaria have an increased risk of anaphylaxis, recent evidence suggests.[1]

Frank J. Twarog, MD, PhD, explained that “more than 30% of children with the condition are prone to anaphylaxis.” Dr. Twarog, an Associate Clinical Professor of Adult and Pediatric Allergy at Harvard Medical School, recommends that all children with cold urticaria be given an epinephrine autoinjector for emergency use.

CLINICAL CHARACTERISTICS

Dr. Twarog and his colleagues assessed the clinical characteristics of cold urticaria in 30 children with the condition. They based the diagnosis of cold urticaria on patient history and used the results of an ice-cube challenge test to support the diagnosis. The children’s mean age at the onset of the condition was about 7 years, and the disorder appeared to be idiopathic in all cases.

A history of asthma or other allergic diseases was common in these children. Fourteen of them had asthma and 15 had allergic rhinitis. Only four children had eczema, however. Positive results for environmental allergens were obtained in 16 of the 19 children who underwent skin testing. Furthermore, of the 28 children for whom a family history was available, 25 had close relatives with atopy.

Despite the children’s history of atopic illnesses, Dr. Twarog does not believe that screening all allergic or asthmatic children for cold urticaria makes sense, because the condition is so rare. However, he acknowledges that “cold urticaria is common enough that physicians should be aware” that it can occur in children.

ANAPHYLAXIS RISK

Dr. Twarog’s group found that 11 of the 30 children with cold urticaria had systemic symptoms. Eight of them experienced a decrease in consciousness (eg, dizziness, faintness, or hypotension), and five developed respiratory distress.

Triggers for anaphylaxis included cold weather and touching cold objects. The most important one, however, was swimming; it was the sole trigger for one third of the patients. “Swimming is a major trigger because of massive exposure to cold,” explained Dr. Twarog. In fact, swimming was the trigger in 10 of the 11 children with systemic symptoms; such reactions are more likely, he noted, when large areas of skin are exposed and when there is a long duration of exposure, as occurs during swimming.

Although the mechanisms behind cold urticaria and its link to anaphylaxis are unclear, Dr. Twarog believes that “changes in skin protein trigger mast cells to release mediators, which can result in anaphylaxis.” It is not known whether any particular child with cold urticaria is at an increased risk of anaphylaxis. Therefore, Dr. Twarog advises children with cold urticaria—and their parents—that they should not jump into a cold swimming pool, and that parents should have rescue medications available when their children go swimming. Premedication with an antihistamine may be helpful as well, but its effect in preventing systemic reactions is unclear.

—Tamara Gibb