Eight extracts from common native allergens, Artemisia annua pollen, Platanus pollen, Humulus pollen, Betula platyphylla pollen, Ambrosia artemisiifolia pollen, Blattella germanica, cat dander, and dog dander were developed for skin prick test (SPT). Since standardization and composition alone cannot guarantee that the allergen extracts are within the concentration range that gives the best chance of an accurate diagnosis, it is necessary to explore the optimal diagnostic concentration (ODC) of allergens in SPT. This study to identify the optimal diagnostic concentration of eight allergen extracts in SPT and assess the safety of simultaneous administration.
Patients with a history of allergic disease were enrolled in this two-part open-label, parallel study. In Study 1, 92 patients were enrolled into eight groups according to their disease-causing allergens and were given three increasing concentrations of the corresponding allergen. In Study 2, 20 patients were divided into two concentration groups and were given all eight allergens. Safety and sensitivity were evaluated to determine the optimal diagnostic concentration. In the study, seven allergen extracts’ sensitivity was > 80% at middle and high concentrations, except for Ambrosia artemisiifolia pollen. The optimal diagnostic concentration (in DU/mL) for eight allergens was 33,333, 12,000, 8667, 50,000, 40,000, 3333, 7000, and 5000. In Study 2, the two groups’ prevalence of adverse events was 70% and 80%, respectively. A total of 10 wheals of 8 patients did not subside < 24 h after SPTs.
The eight allergens showed high sensitivity and safety at a particular concentration, defined as optimal diagnostic concentration. The results support further clinical research of investigated allergens, and our study offers a scheme to determine the ODC of allergens in SPT.