A new study at the University of California San Francisco has found that excessive underarm sweating can be treated effectively with botulinum A neurotoxin (Botox®), a toxin derived from bacteria. "The finding offers patients with this condition a significant alternative to surgery," said Richard Glogau, MD, UCSF clinical professor of dermatology. "This treatment can be completed in an office visit, requires no anesthesia, and absence of sweating is long lasting."
Findings of the study were reported in this month's (September) issue of Dermatologic Surgery.
Excessive underarm sweating, also known as axillary hyperhydrosis is caused by the overstimulation of sweat glands by the autonomic nerves.
"This condition can lead to considerable emotional stress, social stigma, and high costs associated with clothing wear, repair, and cleaning," said Glogau.
Traditional treatments have included over-the-counter commercial antiperspirants, oral medications such as anticholinergic drugs, an electrical treatment known as tap water iontophoresis, and surgery.
Existing non-surgical treatments have had limited effectiveness for excessive sweating or unpleasant side effects, said Glogau.
Surgery for underarm sweating can be effective. However, it can completely prevent sweating in other parts of the body including the upper chest, the arms, and the neck. Because there is no perspiration in these areas, said Glogau, some patients develop compensatory hyperhydrosis, a condition in which other parts of the body sweat in excess. In addition, there is the risk of infection with surgery and a two to five percent failure rate, he added.
In the current study, patients with excessive underarm sweating were treated with injections of Botox®. A poison in high doses, Botox® has been used as a medicine in dilute amounts to treat uncontrolled eye twitching, crossed eyes, muscle spasms and, more recently, to treat facial wrinkles and frown lines, said Glogau. For sweating, Botox® blocks the release of the chemical responsible for stimulating the sweat glands -- acetycholine.
The study involved twelve patients (four males, eight females). Patients received injections of Botox® directly in the underarms. Amounts of the medicine used were similar to those used for wrinkles and frown lines. Patients were followed up at one week and one month. They were asked to return when they noticed sweating had recurred.
All patients reported decrease of underarm sweating within 48 hours of the treatment. Patients remained dry in the underarms for periods ranging from four months to seven months, the average being 5.2 months. Patients then received reinjections of Botox®, which produced similar results. Further follow-up suggests the treatment is effective for five to twelve months. Compensatory hyperhydrosis and other side effects were not reported.
The major limiting factor, said Glogau, is the cost of treatment. Depending on the amount of Botox® required, costs range between $700 to $1000 and the treatment needs to be repeated at least once a year.
