New Directions in Diagnostic Evaluation of Insect Allergy
New Directions in Diagnostic Evaluation of Insect Allergy
Confirmation of sensitization to specific venoms or component allergens is essential for diagnosis and may have some value in predicting the frequency or severity of future sting reactions or the response to VIT or both, but there are other tests that are important in the prediction of risk. Most notably, baseline serum tryptase has been recognized for almost 20 years as an indicator of risk in patients with insect allergy. Elevated baseline serum tryptase has been reported to indicate increased risk of severe anaphylaxis to stings, systemic reactions to VIT, incomplete protection with VIT, and relapse (including fatal reactions) after stopping VIT. Measurement of baseline serum tryptase has become an essential part of the evaluation of patients who are sting allergic, and often leads to further evaluation for potential underlying systemic mastocytosis. It is noteworthy that insect stings are the most common cause of anaphylaxis in patients with indolent systemic mastocytosis.
Increased serum levels of PAF have also been identified as a risk factor for severe and fatal anaphylaxis, including insect stings. This is because of abnormally low levels of PAF acetylhydrolase in these patients. When these measurements become available as commercial assays, they will undoubtedly become part of our repertoire for evaluation of risk in patients with insect sting allergy. One can imagine that future research will identify similar risk-associated and predictive measurements for other mast cell mediators or their metabolic pathways.
Other Diagnostic Tests
Confirmation of sensitization to specific venoms or component allergens is essential for diagnosis and may have some value in predicting the frequency or severity of future sting reactions or the response to VIT or both, but there are other tests that are important in the prediction of risk. Most notably, baseline serum tryptase has been recognized for almost 20 years as an indicator of risk in patients with insect allergy. Elevated baseline serum tryptase has been reported to indicate increased risk of severe anaphylaxis to stings, systemic reactions to VIT, incomplete protection with VIT, and relapse (including fatal reactions) after stopping VIT. Measurement of baseline serum tryptase has become an essential part of the evaluation of patients who are sting allergic, and often leads to further evaluation for potential underlying systemic mastocytosis. It is noteworthy that insect stings are the most common cause of anaphylaxis in patients with indolent systemic mastocytosis.
Increased serum levels of PAF have also been identified as a risk factor for severe and fatal anaphylaxis, including insect stings. This is because of abnormally low levels of PAF acetylhydrolase in these patients. When these measurements become available as commercial assays, they will undoubtedly become part of our repertoire for evaluation of risk in patients with insect sting allergy. One can imagine that future research will identify similar risk-associated and predictive measurements for other mast cell mediators or their metabolic pathways.
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