A unique and effective use of Botox

Frey's Syndrome Treatment

January 11, 2023

Frey's Syndrome

Frey's Syndrome, or gustatory sweating, is a rare, neurological disorder that causes a person to sweat excessively while eating. It most often occurs as a complication of surgery involving the parotid gland. It may also occur following neck dissection, facelifts, or trauma to the area around the gland. This patient had a benign tumor removed from behind her right ear in 1969. To her knowledge, she has been experiencing flushing, slight discomfort, and excessive sweating during meals since that time. Botulinum toxin injections have been shown to be an effective, conservative approach to managing these symptoms without more invasive surgical modalities being required. This proved to be a very helpful solution for the patient

Minor's Starch-Iodine Test & Treatment

The Minor's starch-iodine test consists of painting the ipsilateral face with iodine (allowing to dry) and then dusting that area with starch powder. The patient is given a sialogogue (something that stimulates salivary flow). The dark staining indicates the areas of gustatory sweating. This is approximately 5 minutes after the patient began eating a granola bar with chocolate in it. The positive area was delineated using white eyeliner and then gridded with 1 cm2 boxes after proper cleansing with 70% Isopropyl alcohol. 2 units of Botox (Botulinum Toxin Type A) was delivered intradermally per each 1cm2 area on the affected side. BD 8mm 31 gauge insulin syringes were used to inject a pre-prepared 1:1 ratio of toxin. 30 units in total were administered for the first round of treatment.


The patient returned for a follow-up approximately 7 weeks later reporting significant improvement to her symptoms. The sweating, redness, and discomfort around and below the ear had been completely eliminated. She was noticing some "tackiness" of the skin more on the cheek, stating that these may have been areas that were always affected but that the most noticeable areas were around the ear. A 2nd Minor's test was performed, and the results fell in line with her reported areas of sweating. A second round of intradermal injections were administered for a total of 44 units.

Complete Symptom Resolution

Pt returned for another 7 week follow-up after the second round of treatment, reporting complete elimination of her past symptoms. She has experienced no pain, discomfort, redness, or sweating since the second round of Botox took effect. The photo above was taken after 10 minutes of eating the same type of bar used in each test. As you can see, the test showed no areas of gustatory sweating. This patient had been dealing with these uncomfortable symptoms for decades and can now enjoy food without discomfort or embarrassment.

About The Author

Dr. Greg Feldman has completed over 1500 hours of continuing education following his graduation from the University of Florida College of Dentistry. To put this into perspective, dentists are only required to take 30 hours of continuing education every two years. This means that Dr. Feldman has already taken 100 years of dental education in his relatively young career. He is an avid learner and a lifelong student of dentistry. As a Master of the Academy of General Dentistry and a Fellow of the International Congress of Oral Implantologists, Dr. Feldman has achieved a level of recognition in the field of dentistry that few have ever reached. With this in mind, you can rest assured that anything he writes about on this blog is well researched and backed by scientific evidence and his extensive training.

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