Anaphylaxis: risk factors for recurrence.
BACKGROUND
There are few studies on the incidence or recurrence of anaphylaxis.


OBJECTIVE
To examine the incidence of anaphylaxis and risk factors for recurrence.


METHODS
A prospective study of 432 patients referred to a community-based specialist practice in the Australian Capital Territory with anaphylaxis, followed by a survey to obtain information on recurrence.


RESULTS
Of 432 patients (48% male, 73% atopic, mean 27.4 years, SD 19.5, median 26) with anaphylaxis, 260 patients were seen after their first episode; 172 experienced 584 previous reactions. fifty-four percent of index episodes were treated in hospital. Aetiology was identified in 91.6% patients: food (61%), stinging insects (20.4%) or medication (8.3%). The minimum occurrence and incidence of new cases of anaphylaxis was estimated at 12.6 and 9.9 episodes/100,000 patient-years, respectively. Follow-up data were obtained from 304 patients (674 patient-years). One hundred and thirty experienced further symptoms (45 serious), 35 required hospitalization and 19 administered adrenaline. Accidental ingestion of peanut/tree nut caused the largest number of relapses, but the highest risk of recurrence was associated with sensitivity to wheat and/or exercise. Rates of overall and serious recurrence were 57 and 10 episodes/100 patient-years, respectively. Of those prescribed adrenaline, 3/4 carried it, 2/3 were in date, and only 1/2 patients faced with serious symptoms administered adrenaline. Five patients each developed new triggers for anaphylaxis, or re-presented with significant psychiatric symptoms.


CONCLUSIONS
In any 1 year, 1/12 patients who have suffered anaphylaxis will experience recurrence, and 1/50 will require hospital treatment or use adrenaline. Compliance with carrying and using adrenaline is poor. Occasional patients develop new triggers or suffer psychiatric morbidity.
Mullins
R J
RJ
University of Canberra (Associate Professor), Canberra, University of Sydney (Senior Lecturer), Sydney, Australian National University (Clinical Senior Lecturer), Canberra, Australia. rmullins@allergycapital.com.au
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000707:Anaphylaxis / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology*; D000818:Animals; D020958:Australian Capital Territory / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004837:Epinephrine / Q000627:therapeutic use; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D005512:Food Hypersensitivity / Q000150:complications / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D007299:Insect Bites and Stings / Q000150:complications / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012621:Seasons; D012882:Skin Tests / Q000379:methods
D004837:Epinephrine