Abstract: Objective This study aimed to explore factors influencing a positive skin prick test for Dermatophagoides farinae(SPT-DF)in patients with allergic rhinitis(AR)and the correlation between positive SPT-DF results and AR symptoms. Methods SPT-DF was performed for suspected AR patients using SPT diagnostic reagents, and 764 SPT-DF-positive results were analyzed statistically. Results Of 764 SPT-DF-positive patients, 18(2.36%)were positive level “+”(level one); 23(3.10%)were positive level “++”(level two); 196(25.65%)were positive level “+++”(level three); and 527(68.98%)were positive level “++++”(level four). The differences in positive levels between SPT-DF-positive patients in six age groups(0-4 years, 5-14 years, 15-29 years, 30-44 years, 45-59 years, and 60-69 years)were statistically significant(χ2 = 20.138, P=0.001), and SPT-DF-positive levels decreased with advancing age-group ranges. There were no significant differences in positive levels between male and female SPT-DF-positive patients(Z=-1.503, P=0.133). In the age groups 15-29 years and 30-44 years, the positive level differences between male and female SPT-DF-positive patients were statistically significant(15-29 years, Z=-2.337, P=0.013; 30-44 years, Z=-3.129, P=0.001), with the positive levels of female patients being higher than those of male patients. Of 764 patients, 332(43.46%)had AR only. There were 432(56.54%)patients with other allergic diseases(allergic conjunctivitis, asthma, and allergic dermatitis), 367(48.03%)patients with two kinds of allergic diseases, 35(4.58%)patients with three kinds, and 30(3.93%)patients with four kinds. The number of patients with allergic diseases were as follows: allergic conjunctivitis, n=331; allergic dermatitis, n=56; and asthma, n=42. Among 764 SPT-DF-positive patients, differences in the positive levels between SPT-DF-positive patients with different numbers of allergic disease types were statistically significant(χ2=26.065, P=0.000), and the higher the number of allergic disease types, the higher the SPT-positive level. There were no significant differences in scores with respect to sneezing(F=0.207, P=0.891), runny nose(F=0.297, P=0.827), nasal congestion(F=0.174, P=0.913), nasal itching(F=0.256, P=0.857), itchy eyes(F=0.044, P=0.987), tearing(F=0.154, P=0.926), and the total symptom score(F=0.211, P=0.884)between different SPT-DF-positive levels. There was also no correlation found between SPT-DF-positive levels and scores with respect to sneezing(r_s=-0.036, P=0.387), runny nose(r_s=-0.034, P=0.392), nasal congestion(r_s=-0.026, P=0.433), nasal itching(r_s=0.056, P=0.141), itchy eyes(r_s=-0.039, P=0.379), tearing(r_s=-0.041, P=0.374), and total symptom score(r_s=0.032, P=0.397). Conclusion The SPT-DF-positive levels are affected by age and the number of allergic disease types in patients with AR, but are not affected by sex differences. The SPT-DF-positive levels have no correlation with AR symptom scores.

Key words: Allergic rhinitis, Dermatophagoides farinae, Skin prick test