Background: The actual incidence of anaphylaxis is unknown. Periodical study of the anaphylaxis in different countries will raise the awareness to improve further the prevention and care.
Methods: To investigate anaphylaxis among inpatients in the previous decade, we conducted a retrospective study of adult patients between 1992 and 2001 at a tertiary care center in Bangkok.
Results: Of 448,211 admissions, 80 events of anaphylaxis in 79 patients (0.017%) were found. The incidence had increased from 2.6 to 46 per 100,000 inpatients. Mean age +/- SD was 36 +/- 16 years-old, with an equal male:female ratio. Drugs, mainly antibiotics and nonsteroidal anti-inflammatory agents, (48%) and food (31%) were the most common causes. Over-the-counter medication and multiple drug use were responsible for up to a half of the unspecified drug causes. There was no fatality. 84% received epinephrine, but in only 7% it was given intramuscularly. Fifteen cases (20%) had a history of prior anaphylaxis, nonetheless only one had received prefilled epinephrine.
Conclusions: The rise in the incidence of anaphylaxis over the two decades of the study period is alarming. Raising the awareness of anaphylaxis management among healthcare providers and the public is warranted.