Background and objective: Pollens from the Cupressaceae family are considered important allergens in the Mediterranean area, though reports of the prevalence of allergic symptoms have ranged from 1.04% to 35.4%. Our aim was to detect the prevalence of cypress pollen sensitization and determine its clinical importance in patients with seasonal respiratory allergy.

Methods: We used skin prick tests (SPT) and serum specifi c IgE assays to reveal sensitization to cypress pollen. In patients who showed positive results to cypress pollen, a nasal provocation test (NPT) with pollen extract was used to assess the target organ response.

Results: Sixty-fi ve (14.3%) of 455 patients showed positive SPT responses to Cupressus sempervirens extract. Only 1 patient was monosensitized while 64 patients were polysensitized. Among those, 2 pollen cosensitizations were found to be signifi cant (86% were cosensitized to grasses and 72% were cosensitized to olive (P < .001). Serum specific IgE to cypress pollen was measured in 50 of the 65 patients; fi ndings were positive for 37. When these 37 patients underwent NPT with C sempervirens allergen extract, only the single monosensitized patient had a positive NPT.

Conclusion: A positive SPT to cypress pollen may not refl ect the true prevalence of sensitization. We assume that in the absence of a positive NPT, positive SPT results might be related to the presence of cross-reactivity between pollen species.

Key Words: Allergy. Cypress pollen. Cross-reactivity. Nasal provocation.