Not only gustatory sweating and flushing: Signs and symptoms associated to the Frey syndrome and the role of botulinum toxin A therapy

Background The classic symptoms of Frey syndrome are gustatory sweating and flushing. Aims of the study were to describe prevalenceand severity of typical and atypical presentations of the disorder and to assess the effects of botulinum neurotoxin A (BoNT-A) therapy in patients with Frey syndrome after parotidectomy. Methods In this prospective, observational study on 18 patients, we assessed symptom severity before therapy, after 15 days, 1, 3 and 6 months' follow-up with the sweating-flushing-itch-paresthesia-pain (SFIPP) Frey scale specifically designed by the authors themselves for this study. Results Before BoNT-A injection, all patients (100%) complained gustatory sweating, 80% paresthesia, 77% gustatory flushing, 60% pain and 60% gustatory itch. The SFIPP-Frey overall score and the symptom-specific ones decreased significantly at each post-therapy control. Conclusions The prevalence of "unusual" manifestations is not negligible. BoNT-A improves symptoms severity. The SFIPP-Frey scale may be useful to assess symptoms and to monitor post-therapy outcomes.