Background: Even though the Parietaria pollen season may be rather long, many physicians think that Parietaria pollen is a perennial allergen present along the whole year. In fact, many doctors prefer to prescribe allergen immunotherapy (AIT) in Parietaria allergic patients, using continuous courses. On the other hand, physicians usually prescribe pre-co-seasonal AIT course for other pollen allergies.
Objective: This study aimed at investigating whether a single pre-co-seasonal AIT course could be effective in Parietaria allergic patients.
Methods: Globally, 59 subjects (31 males, mean age 35.9 years) were retrospectively evaluated. All were treated with SLIT as a pre-co-seasonal course: 33 with Parietaria extract and 26 with birch extract. Patients' perception of symptom severity and medication use was assessed by visual analogue scale, comparing the previous pollen season and the present.
Results: The Parietaria 2012 pollen season started from the 60(th) day and ended at the 205(th) day of 2012. A single pre-co-seasonal SLIT course was able to significantly (p < 0.0001) reduce symptom severity and medication use.
Conclusion: This preliminary study demonstrates that Parietaria pollen season in Genoa lasted about six months and a single pre-co-seasonal SLIT Parietaria course could be sufficient to reduce symptom severity and medication use.
Keywords: Parietaria; allergen immunotherapy; allergic rhinitis; medications; pre-co-seasonal course; symptoms.