Predictors of severe anaphylaxis in Hymenoptera venom allergy: The importance of absence of urticaria and angioedema.

BACKGROUND

Severe anaphylaxis (SA) in Hymenoptera venom allergy has been associated with a number of risk factors. However, the effect of several of those risk factors on the severity of anaphylaxis is poorly defined.

OBJECTIVE

To evaluate risk factors for SA in Hymenoptera venom allergy.

METHODS

We evaluated data from 500 patients who were referred to our department for the diagnosis of Hymenoptera venom allergy during a period of 11 years to identify risk factors for SA.

RESULTS

Six significant risk factors for SA were identified (P < .05): short interval from sting to reaction, absence of urticaria or angioedema (U/A) during anaphylaxis, older age, male sex, elevation of baseline serum tryptase (BST) level, and diagnosis of systemic mastocytosis. Moreover, elevation in BST level was significantly associated with the absence of U/A and older age. No association could be established between SA and comorbidities, concurrent cardiovascular medication, or the severity of the systemic reaction during the initiation of venom immunotherapy.

CONCLUSION

Apart from BST and older age, male sex, short interval from sting to reaction, and absence of U/A are also risk factors for SA. The association between elevated BST level and SA was largely confined to those who had an absence of U/A after field sting, possibly because of the higher risk of concurrent systemic mastocytosis. Patients with an SA after a field sting do not have an elevated risk of systemic reactions during the initiation of venom immunotherapy compared with patients with mild anaphylaxis; therefore, additional preventive measures are not necessary.