Oral-pharyngeal and skin testing in the diagnosis of food allergy to tangerine

The purpose. To assess the diagnostic significance of the oral-pharyngeal challenge test with extract (1) and tangerine juice (2) in comparison with intradermal allergy test with tangerine extract and prick-prick test with fresh tangerine in patients with food allergy. Materials and methods. The peroxidase activity of the oral fluid was assessed in healthy individuals after breakfast. Patients with allergic reactions to tangerine (study group), patients with allergic rhinitis, bronchial asthma and hay fever, but without food allergy (risk group) and healthy individuals (control group) underwent oral-pharyngeal challenge test with tangerine allergen extract (20 PNU/ ml)/freshly squeezed tangerine juice (1 PNU/ml) followed by evaluation of peroxidase activity of the oral fluid, intradermal tests with tangerine extract and prick-prick tests with fresh tangerine were performed. Results. The majority of patients with food allergy to tangerine had polyvalent sensitization to household/epidermal (76%) and pollen allergens (39%). The most common manifestation of tangerine allergy were urticaria (48% of cases), bronchospasm (21% of cases) and oral allergy syndrome (10%) After breakfast, the optical density of the oral fluid decreased compared to the initial level in all healthy volunteers (p=0,001). After oral-pharyngeal challenge test with tangerine extract (1) and juice (2), the average increase of peroxidase activity of the oral fluid in patients with food allergy was М1=+23,5 [7,0;40,1], М2=+41,4 [4,2;78,6], which was significantly higher than in controls M1=-2,1 [-9,6;5,4], p1=0,038, M2=+4,4 [-9,6;18,4], p2=0,047 and in patients with chronic allergopathology, but without food allergy M2=+0,4 [-13,1;13,8], p2=0,049. The positive prick-prick test with fresh tangerine was observed in 44% of patients in the study group, the standard intradermal test with tangerine allergen extract - in 12%. The intradermal test with tangerine extract and prick-prick test with fresh tangerine were negative in patients without food allergy and healthy individuals. Conclusions. The oral-pharyngeal challenge test with extract (1) and tangerine juice (2), prick-prick test with fresh tangerine (3) can be used in the diagnosis of food allergy to tangerine. The sensitivity and specificity of the challenge test with tangerine allergen extract were 53% and 88%, with tangerine juice – 44% and 89%, prick-prick test with fresh tangerine – 44% and 100%. The proposed tests had a higher diagnostic efficiency than the standard intradermal test with tangerine allergen extract (p1=0,01, p2=0,03, p3=0,039).