OBJECTIVE

To find the lowest effective injection dose of abobotulinum toxin A (Dysport) for allergic rhinitis.

STUDY DESIGN

Dose-escalation randomized controlled trial.

METHODS

We included all patients aged 18 years or older who had persistent allergic rhinitis and positive allergy skin prick test. The patients were randomly allocated to receive 40, 30, or 20 U of abobotulinum toxin A by injection at the inferior turbinate. We followed up on patients for 12 weeks to evaluate nasal symptoms, ocular symptoms, minimum nasal cross-sectional area as measured using acoustic rhinometry, and complications.

RESULTS

Seventeen patients were included in this study, with 7 receiving 20 U of abobotulinum toxin A and 5 each receiving 30 U and 40 U. Abobotulinum toxin A significantly improved nasal congestion, rhinorrhea, sneezing, and loss of smell at 40 U ( < .05) and nasal congestion, sneezing, and loss of smell at 30 U ( < .05). However, at a dose of 20 U, only nasal congestion and loss of smell improved ( < .05). Nasal patency had also significantly improved two weeks after treatment at doses of 40 and 30 U ( < .05). Complications included epistaxis (11.8%) and nasal dryness (23.5%).

CONCLUSION

Abobotulinum toxin A at a dose of at least 30 U effectively reduced most nasal symptoms.

LEVEL OF EVIDENCE

TRIAL REGISTRATION

Clinicaltrials.in.th/ TCTR20200526014.