| Abstract: | BACKGROUND: The intranasal allergen Provocation test (INT) is the standard procedure to verify the effect of an allergen when a nasal allergy is suspected. It may be especially useful if results from skin tests or in vitro tests conflict with those from the history. In the clinical and research setting, INT may be used to study the efficacy of different treatment modalities such as pharmacotherapy or immunotherapy. The technique of INT has not been well standardized in the past. Variations exist in planning the optimum time for testing, especially in seasonal allergies. METHODS: We examined influences of different test dates with regard to the pollen season on the result of INT. A total of 19 patients (eight females, 11 males, aged 26.1 +/- 4.8 years) with a history of at least two years of allergic rhinitis to birch pollen, positive skin prick test, and RAST (> or = CAP class II) to birch pollen. INT was performed during the winter-period after approximately six months without natural pollen exposition (V1), during the birch pollen season (V2) and six weeks after the birch pollen season (V3). Allergens were applied using a pump spray (0.1 ml) in concentrations of 10, 50, 100, 500, 1000, 5000, 10,000, 50,000, and 100,000 SQ units per ml (SQ/ml). RESULTS: The threshold concentrations were significantly lower at V2 (100 SQ/ml) and V3 (500 SQ/ml) if compared to V1 (1000 SQ/ ml). CONCLUSIONS: Seasonal influences should be taken into account when performing INT in birch pollen allergy. |
