A Pilot Study of Transdermal Application of Diphenhydramine to the Nasal Ala in Patients with Allergic Rhinitis and Asthma.

Background: To date, topical allergic rhinitis drugs must be applied intranasally. We studied the efficacy, safety, and impact on co-existing asthma symptoms of transdermal delivery of diphenhydramine through the nasal ala.

Methods: We enrolled outpatients with symptomatic allergic rhinitis and asthma who were on stable medication for at least 4 weeks. Patients applied diphenhydramine ointment, 0.07 g measured with weighing spoon (0.7 mg diphenhydramine), to the nasal ala twice a day for 2 weeks, followed by 2 weeks' washout. Effects were assessed with the Japanese Allergic Rhinitis Standard Quality of Life Questionnaire (JRQLQ) and Self-assessment of Allergic Rhinitis and Asthma (SACRA) and Asthma Control Test (ACT) questionnaires.

Results: Ten patients participated in the study. Two patients experienced acute exacerbation of asthma during the intervention phase, but no other adverse effects occurred. Self-assessments indicated efficacy in treating nasal symptoms in 5 patients. No significant changes in scores were seen, although mean total JRQLQ score showed a numerical improvement (from 34.3 [21.0] to 14.4 [8.8]; P = 0.0547). Asthma symptoms improved subjectively in 2 patients.

Conclusions: The efficacy of transdermal application of diphenhydramine on the nasal ala for treating allergic rhinitis was not conclusive, but appears to be effective in certain patients.