The Leading cause of Anaphylaxis in children and adolescents
Anaphylaxis is becoming more common in children, but underdiagnosis and underreporting make it difficult to diagnose. The aim of this study was to determine the causes of anaphylaxis in children and adolescents in Portugal, in order to improve our understanding of the etiology, clinical symptoms, and management of the condition.

During a 10- year period a nationwide notification system for anaphylaxis was implemented, with voluntary reporting by allergists. Data on 533 patients under 18 years of age with anaphylaxis were included.

--Mean age was 8.5±4.9 years, 61% were male; 45% had asthma.

--Mean age at the first anaphylaxis episode was 5.3±4.7 years (ranging from 1 month to 17 years of age), 63% at preschool age. Most reactions occurred at home (57%).

--Food-induced anaphylaxis was the leading cause (77%). The main culprit foods were cow’s milk (32%), tree nuts (16%), shellfish (13%), egg (12%), fresh fruits (11%), fish (8%) and peanut (8%).

--Other causes included drugs (11%), insect-sting (5%), cold-induced anaphylaxis (4%), exercise-induced (2%), latex (1%) and idiopathic anaphylaxis (1%).

--Most patients (83%) were admitted to the emergency department; only 46% received adrenaline treatment.

--Recurrence of anaphylaxis occurred in 41% of the patients (3 or more episodes in 21%). An adrenaline autoinjector was used in 9% of the patients.

Finally, food is the leading cause of anaphylaxis in the Portuguese pediatric population. The high recurrence of anaphylaxis and undertreatment with adrenaline demonstrate the need to strengthen both the diagnosis and clinical management of this life-threatening condition.