Louise Gagnon is a medical writer and editor based in Oakville, Ontario, Canada.
Botulinum toxin type A (Botox Allergan) is the gold standard to treat axillary hyperhidrosis, but it also can be administered to treat palmar hyperhidrosis or plantar hyperhidrosis. In very rare instances, it can be used to treat the mid-face. There is not a standard dosing schedule in using botulinum toxin type A to treat hyperhidrosis.
- It’s crucial to perform an iodine starch test before using onobotulinumtoxinA (Botox, Allergan) to treat axillary hyperhidrosis, according to a dermatologist in private practice in Zurich, Switzerland.
"We can now state that botulinum toxin is the gold standard for axillary hyperhidrosis," says Oliver P. Kreyden, M.D.
"Botulinum toxin is the first-line treatment for axillary hyperhidrosis," says Dr. Kreyden, formerly of the department of dermatology at the University Hospital in Zurich, Switzerland. "However, it is important to perform a minor starch test. This test is easy to do and is not expensive."
The total number of sweat glands is somewhere between two and four million, and a vast minority (5 percent) are active at the same time, suggesting huge potential for sweat production.
Indeed, the emergence of botulinum toxin has been of enormous benefit in managing axillary hyperhidrosis. Two decades ago, it was a condition for which there were only few effective and safe therapies. The diagnosis of primary hyperhidrosis is typically based on a patient"s history and visible signs of sweating, Dr. Kreyden notes.
The use of the starch test highlights through discoloration the sites where the solution should be injected.
"You mark the area you want to inject and then you plan each injection point," says Dr. Kreyden, noting clinicians may also want to take photographs to have a visual record of the stains with the starch test.
There is not a uniform approach to treating hyperhidrosis, Dr. Kreyden tells Dermatology Times. Indeed, therapy needs to be individualized, taking into account the area of the body that is being treated and the degree of excessive sweating of the patient.
"Forget the rule of one vial per patient," Dr. Kreyden says. "You have to adapt the dosage to the patient that you have in front of you."
Specifically, he recommends a dosage of two units of botulinum toxin type A on each injection point.
If the outcome of the treatment is not satisfactory, it is recommended to increase the number of injection sites rather than increase the dosage of botulinum toxin, according to Dr. Kreyden. ":You have to play with the injection points, but not increase the dose," he says.
A study he performed found diffusion of botulinum solution was comparable when a 5 ml solution was used and when a 10 ml solution was used. ":According to the amount of sweating, some patients need more injections,": he explains.
The use of anesthesia is not necessary for managing axillary hyperhidrosis, as it is not painful. In using botulinum toxin to treat palmoplantar hyperhidrosis - excessive sweating of the hands and/or feet - patients experience more pain with injections of botulinum toxin. Consequently, Dr. Kreyden suggests pre-treatment with iontophoresis with a 10 percent lidocaine solution for 30 minutes.
With this treatment, we achieve a good superficial anesthesia that allows us to perform cryotherapy on each injection point to minimize the pain of the injections.
Alternatively, tap water iontophoresis can be performed instead of botulinum toxin type A injection for palmoplantar hyperhidrosis. This treatment is well-tolerated, effective, inexpensive and noninvasive. Additionally, patients can perform the therapy in the comfort of their own homes after they bought the iontophoresis unit, Dr. Kreyden says.
Patients should apply the therapy for 15 minutes on each hand, for palmar hyperhidrosis treatment, or 15 minutes on each foot, for plantar hyperhidrosis. If the hyperhidrosis affects both the hands and feet, the treatment can easily be performed on the hands and feet at the same time. Another advantage of the tap water iontophoresis is that it is inexpensive treatment compared to botulinum toxin, which can require two or three vials of solution per hand or per foot, respectively, to treat palmar or plantar hyperhidrosis.
As the drug itself is very expensive, this makes the whole treatment quite costly, according to Dr. Kreyden.
To treat focal hyperhidrosis on the forehead, botulinum toxin is also a treatment option, he notes. Clinicians need to be careful in injecting the solution, remaining 2 cm above the eyebrow to avoid ptosis of the eyelids or the feeling of a heavy front, respectively.
In very rare cases, botulinum toxin is being used for the mid-face. In this instance, it’s wise to use a very low dose of high-diluted solution, about 0.5 ml using 0.5 units per injection point, suggests Dr. Kreyden. However, strictly very trained physicians with a huge experience injecting botulinum toxin type A should be performing this indication.
Botulinum toxin is also being used to treat conditions such as Ross syndrome or Frey’s syndrome, Dr. Kreyden adds.