[Anaphylaxis and biphasic reaction in a children hospital]

Anaphylaxis is an acute multi-systemic and potentially fatal reaction, resulting from the exposure to antigens. There are few detailed reports of children with anaphylaxis. We studied the actual condition of an anaphylaxis including biphasic reaction.

This is a retrospective case study of children presenting to the Emergency Department of the National Center for Child Health and Development with anaphylaxis between 2002 and 2010. Etiology, age, sex ratio, clinical features, and management were examined.

The median age of the patients was 36 months. Boys were predominant (63%). Seven cases developed anaphylactic shock, but all survived. As causes of anaphylaxis, food was identified in 85% of the patients, including eggs, dairy products and nuts, and drugs were identified in 3% of the patients. Initial symptoms consisted of mucocutaneous lesions (90%) and respiratory symptoms (71%). Epinephrine was given in 75 patients (22%). The biphasic anaphylactic reaction was observed in 3 out of the 340 cases (0.9%). In age, sex, grade and symptoms, there was no significant difference between patients with biphasic anaphylactic reaction and monophasic reaction.

We clarified that the incidence of biphasic anaphylactic reaction was 0.9% in pediatric patients for the first time in Japan.