Skin prick tests (SPTs)
SPTs were performed for the 14 most common inhalant allergens (Allergopharma GmbH & Co, Reinbek, Germany), includingDermatophagoides pteronyssinus (Der p ),Dermatophagoides farina (Der f ), dog dander, cat epithelium, cockroach, Alternaria alternata , Aspergillus fumigatus , grass pollen mixture, alder, birch, oak, ragweed, mugwort, alder, and four food allergens, including peanuts, egg whites, cow’s milk, and soybeans at 3 and 7 years of age.19,20Histamine (10 mg/mL) was used as the positive control, and normal saline was used as the negative control. A mean wheal size of 3 mm or larger for allergens and histamine after 15 minutes was considered a positive result. Atopy was defined as the presence of one or more positive test results to any of the 18 allergens assessed using SPTs.19,20