We aim to describe the epidemiology and triggers of anaphylaxis related Emergency Department visits in children and adults in Singapore.
METHOD
We performed a prospective study of patients visiting the Emergency Department(ED) for anaphylaxis. We collected data from the emergency departments of three major tertiary hospitals from April 2014 to March 2015. The electronic records of patients with the diagnoses of allergy, angioedema, urticaria and anaphylaxis (ICD codes 9953, 9951, 7080, 9950, 7089) were obtained.
RESULTS
There were 271 cases of anaphylaxis identified, making up 7% of all ED visits for allergy-related symptoms. The median age was 22 years (range 5 months-89 years). Children (below 16 years) made up 35% (94/271) of the cohort, with 139 males (51%). Patient ethnicity included Chinese (180 cases, 66%), Malay (44, 16%), Indian (18, 7%) and others (29, 11%).
The most common trigger was food (n=126, 46%), followed by drugs (n=50, 18%) and stinging insects (n=14, 5%). The trigger could not be identified at initial presentation in 62 cases (23%). The most common food allergen was shellfish (n=36, 29%), followed by peanuts and other nuts (n=16, 13%). There were 2 new cases of galacto-oligosaccharide allergy that were confirmed on follow-up.
Age distribution varied with the triggering factor. Those with drug-induced anaphylaxis were older than those with food allergy (mean age 32.5 vs 24.5 years, p = 0.015). All cases of insect-related anaphylaxis occurred in adults (age range 22-68 years). The cases of shellfish anaphylaxis were older than those with peanut/tree-nut anaphylaxis [mean 29.7 years (range 6-75, SD 19.7 years) vs mean 14.2 years (range 2-51, SD 13.9 years); p = 0.006].
The hospitalization rate was 52%. On both univariate and multiple regression analysis, the only significant factor associated with hospitalization was the age of the patient (Spearman’s correlation coefficient 0.169, p=0.006).
CONCLUSION
Food and drug allergies are common causes of anaphylaxis. Shellfish is the most common food allergen. Anaphylaxis caused by drugs, stinging insects and shellfish was more common in adults, whilst anaphylaxis caused by peanuts and tree nuts is more common with children.