Anaphylaxis: Ten-year retrospective study from a tertiary-care hospital in Asia.

Background: The study of anaphylaxis in different geographic areas raises the awareness to improve prevention and medical care.
Objective: To investigate the incidence, causes, characteristics, and management of anaphylaxis in Chiang Mai, Thailand.
Methods: We performed a retrospective review, based on ICD-10 electronic medical records of patients who attended the Out-Patient and Emergency Departments at Chiang Mai University Hospital from January 2007 to December 2016.
Results: A total of 441 episodes of anaphylaxis in 433 patients were analyzed. Three-hundred and sixty-two (84%) were adults and 71 (16%) were children. Anaphylaxis was common in the second and third decades of life. The incidence rate for all causes of anaphylaxis was 3.9 episodes per 100,000 out-patient and emergency visits per year. The rate in children was more frequent than in adults. Foods were the most common culprit (47%), followed by insect stings (23%) and drugs (18%). Severe anaphylaxis, defined as the loss of consciousness, hypotension, respiratory failure, or cyanosis were found in 163 events (37%). The time lapses between exposure with an allergen and the onset of symptom less than 30 minutes and triggered by insect stings were significantly associated with severe anaphylaxis. Biphasic reactions occurred in 6 patients (1.4%). Adrenaline injections were prescribed in most of patients (90%). There were no fatality cases in the past 10 years.
Conclusions: The incidence of anaphylaxis in our hospital appears more often in children than in adults. The frequency in adults trends to be increasing. Food and insect stings are the common causative agents.