Difference according to Interpretation Methods in Allergic Skin Test

ABSTRACT

BACKGROUND AND OBJECTIVES: The skin prick test is a widely used test that uses three methods (allergen/histamine ratio method, erythema size method, and wheal size method) to interpret the results. However, there has been no comparison of these methods. The aim of this study is to compare the three different interpretation methods and define the relationship among them. SUBJECTS AND METHOD: A total of 139 patients who visited our allergy clinic complaining of nasal symptoms were enrolled. Three interpretation methods were used for defining positivity in the skin prick test, and their results were compared. The validity of each interpretation method was evaluated by total nasal symptom score. RESULTS: Positivity in the skin prick test was reported in 48.2% of patients according to the allergen/histamine ratio method and in 64.0% of patients according to the wheal size method and erythema size method. The proportion of subjects who showed a negative result with the allergen/histamine ratio method but positive results with the wheal size method or erythema size method was 15.8%. This group had a significantly higher total nasal symptom score, especially rhinorrhea and nasal obstruction, than subjects who showed negative results on all three methods. CONCLUSION: When diagnosing allergic rhinitis patients using the skin prick test, the wheal size method and erythema size method should be considered rather than the allergen/histamine ratio method.