Cupressus arizonica: an emerging aeroallergen for East Mediterranean children

Cupressus sempervirens is a tree native to the Mediterranean region. We aimed to investigate the frequency of sensitization/allergy to Cupressus arizonica pollen, which is not native to Anatolia.

Patients aged 5-18 years who underwent respiratory allergy screening in Türkiye's largest referral center over a 1-year period were reviewed retrospectively for a diagnostic study of Cupressus allergy.

Of 246 patients, 207 (67.6% male) with a median age of 11.7 (IQR 9.2-15) years were found to be aeroallergen-sensitive and C. arizonica (32%) was the second most common sensitivity after grass pollen (83.6%). In the C. arizonica-sensitive subgroup, only 3% (2/67) were monosensitive, and grass (77.6%), cat (38.8%), and weeds (38.8%) were the most common co-sensitivities. Cup a 1 specific IgE (sIgE) was measured in 26 patients with C. arizonica sensitivity and all were found to be positive. A nasal allergen challenge (NAC) was performed for 44 of 67 patients with C. arizonica sensitivity, and 13 of 44 patients had a positive outcome (NAC+) at the highest two extract concentrations. The Cupressus wheal sizes and Cup a 1 sIgE levels of the NAC+ subgroup were higher than those of the NAC- subgroup but reached significance only for wheal size [6 (5-7.5) vs. 4.5 (4-6), p=0.004]. The NAC+ subgroup reported more frequent nasal discharge, congestion, and eye symptoms than the NAC- subgroup during the relevant pollen season.

C. arizonica sensitivity has increased in the East Mediterranean region, similarly to North Mediterranean data, and this is associated with the presence of allergy both clinically and in laboratory findings. C. arizonica should be included in the aeroallergen screening panels of children from the East Mediterranean.