For the IDT, 0.02–0.03 mL of drug solution was injected using a 29.5 gauge needle, producing a 4 mm injection wheal. The SPT was considered positive when the wheal diameter was ≥3 mm at 20 min, while the IDT was considered positive if the reading wheal (RW) doubled the injection wheal (IW) at 20 min (the RW/IW ratio ≥2).