Deliberate hymenoptera sting challenge as a diagnostic tool in highly selected venom-allergic patients.

BACKGROUND

Open environment and working conditions close to abundant insects of the order Hymenoptera should be avoided as much as possible by patients allergic to Hymenoptera venom who do not receive venom immunotherapy. After having experienced accidental field re-stings not resulting in a systemic reaction, some of these patients may be willing to resume normal life and working habits. Since venom-specific IgE usually remains elevated in these patients, repeated skin tests or RASTs are not helpful in identifying disappearance of their venom allergy.

OBJECTIVE

The purpose of this study was to evaluate the usefulness of deliberate live sting challenge as a diagnostic tool in highly selected venom-allergic patients who had initially refused venom immunotherapy.

METHODS

Two cases are reported of bee venom-allergic patients who had previously refused venom immunotherapy and subsequently experienced honeybee field re-stings not resulting in systemic reactions. Two to three years later, their skin tests remained positive for bee venom. A third patient allergic to Vespa orientalis who had negative skin tests to all available venoms was denied venom immunotherapy due to lack of proper commercial venom. Because none of the patients was receiving venom immunotherapy the military service personnel concluded they still had venom allergy and rejected them from the highly prestigious service. All three patients were anxious to confirm the disappearance of their venom allergy and we used deliberate live sting challenges for that purpose.

RESULTS

Two to three years after their initial systemic reactions live sting challenges were well tolerated by the three patients. They felt free to resume their normal life habits and were allowed to begin military service without further limitations.

CONCLUSION

Deliberate insect stings using appropriate safety precautions should be considered a diagnostic tool in selected allergic patients who do not receive venom immunotherapy but in whom a reliable history of negative field re-stings can be obtained despite positive skin tests and in those who continue to have inconclusive venom skin tests.