Ragweed allergy: Pollen count and sensitization and allergy prevalence in two Italian allergy centers.

Background: Ragweed allergy represents a challenge for allergists due to its increase in some geographic areas, mainly northern Italy.
Objectives: To compare two allergy centers in northern Italy by analyzing both the pollen count and the patient characteristics (sensitization and allergy prevalence) over a 10-year period.
Methods: Pollen counts for 10 years (2004-2013) were evaluated and compared in the two centers. Characteristics of patients who were sensitized and allergic to ragweed were analyzed.
Results: There was a significantly higher pollen count in Busto Arsizio than in Novi Ligure (p < 0.001). The patients who were seen in the Busto Arsizio center showed more frequent sensitization (p < 0.01) and allergy (p < 0.05) to ragweed than patients who were seen in the Novi Ligure center. The pollen count was significantly (p < 0.01) associated with sensitization and allergy difference. Allergic asthma was more frequent (p < 0.05) in Busto Arsizio.
Conclusions: The pattern of sensitization and allergy prevalence seemed to be associated with ragweed pollen pressure, such as quantity. The knowledge of the pollen count is relevant in clinical practice, mainly for the management of patients with allergy.