In the area of Madrid (Spain) Quercus spp. pollen is released from April to mid May. There has been an increase of total pollen count in the last years. In 1980 total pollen count was 2.700 grains/m3 while in 2015 was of 20.000 grains/m3. The major allergen described from Quercus albus (Que a 1) is a homologue of Bet v 1.This study was done to know the sensitization to this pollen in the area of Madrid which a free birch-pollen area.
During 2014, 297 patients with rhinitis, rhino-conjunctivitis and/or asthma during the months of April-May in Madrid were included. Skin prick tests (SPT) were performed with common aeroallergens in our area, and extracts of Quercus robur and Quercus ilex from ALK Labs. and Leti Labs (Spain).Nasal provocation tests with Quercus robur (Bial-Aristegui, Spain) were performed in 10 patients with positive SPT to Quercus r.
From 297 patients studied, 23 (7,7%) had positive SPT to Quercus robur, 11 of them had also positive SPT to Quercus ilex. There was no difference between extracts of both laboratories. None of the 23 patients were sensitized only to Quercus r. and 11 of them (47.8%) had + SPT to profilin. All nasal provocations tests were negative.
In spite of high concentration of Quercus pollen in the area of Madrid, the rate of sensitization to this pollen is quite low and with no clinical relevance due to negative nasal challenge tests results. Sensitization to this pollen may be due to cross-reactive pollen allergens.