Cause and Clinical Presentation of Anaphylaxis in Singapore: From Infancy to Old Age.

BACKGROUND: The study objective was to compare age-related differences in the cause and clinical presentation of anaphylaxis.

METHODS: We conducted a prospective study of patients visiting the emergency department for anaphylaxis. Data were collected from 3 emergency departments from 1 April 2014 to 31 December 2015. Patient electronic records with the diagnoses of allergy, angioedema, urticaria, and anaphylaxis (ICD-9 codes 9953, 9951, 7080, 9950, 7089) were screened and cases fulfilling World Allergy Organisation criteria for anaphylaxis were included.

RESULTS: A total of 426 cases of anaphylaxis were identified with a median age of 23 years (range 3 months to 88 years and 9 months). The causes of anaphylaxis were food (n = 236, 55%), drugs (n = 85, 20%), idiopathic (n = 64, 15%), and insect bites or stings (n = 28, 7%). The most common food was shellfish (n = 58, 14%) and the most common drugs were non-steroidal anti-inflammatory drugs (n = 26, 6%). There were more cases of food anaphylaxis in children than in adults (72 vs. 42%, p < 0.001) and more cases of drug anaphylaxis in adults than in children (28 vs. 10%, p < 0.001). Compared to patients of other ages, infants and young children had more gastrointestinal symptoms (adjusted odds ratio [aOR] 2.1, 95% CI 1.1-3.9), while schoolchildren and adolescents had more respiratory symptoms (aOR 2.7, 95% CI 1.4-5.2). Adults had more cardiovascular symptoms (aOR 2.9, 95% CI 1.8-4.6) and hypotension (aOR 3.7, 95% CI 2.1-6.8) compared to children. However, 42% of the infants lacked blood pressure measurements.

CONCLUSIONS: Knowledge of age-related variation in the cause and clinical presentation of anaphylaxis aids in diagnosis and acute management.