Microwave Treatment Effective for Axillary Hyperhidrosis

An Expert Interview With Mark Lupin, MD

Fran Lowry

April 30, 2012

April 30, 2012 (Kissimmee, Florida) — Editor's note: In 2011, the US Food and Drug Administration approved a new technique for the treatment of axillary hyperhidrosis, or excessive underarm sweat, that uses microwaves to destroy sweat cells.

The miraDry System, manufactured by Miramar Labs, noninvasively delivers energy to the underarm area where the sweat glands are located, creating localized heat to eliminate the glands.

The effects are long-lasting because the sweat glands, once destroyed, do not regenerate, according to Mark Lupin, MD, a dermatologist from the University of British Columbia in Vancouver, Canada.

Dr. Lupin presented the 18-month follow-up data from a study that assessed the efficacy and safety of the miraDry System here at the American Society for Laser Medicine and Surgery (ASLMS) 2012 Annual Conference. He spoke with Medscape Medical News about the treatment.

Medscape: How common is axillary hyperhidrosis?

Dr. Lupin: It is estimated that 1 in 5 adults are affected by severe sweating, based on 2 different surveys in the United States. About 4% of the American population is diagnosed with axillary, or underarm, sweating and another 17% report that their sweat is excessive to the point that it bothers them but they have not discussed the problem to their doctors.

People think that it is not a medical condition and that it may be normal or they're not aware that there are treatment options other than antiperspirants.

Medscape: What causes axillary hyperhidrosis?

Dr. Lupin: This is excess sweating beyond what is considered normal to maintain consistent body temperature. There can be a familial tendency. With generalized sweating, we make sure there are no medical reasons, like thyroid disease or diabetes. But for underarm sweating, it's a variation of normal. The amount of sweating is sometimes 4 to 5 times what is normal; we don't measure it by just the amount of sweat, but how it impacts people's daily lives.

Medscape: What were the treatments for this condition in the past?

Dr. Lupin: Treatment options are antiperspirants, including over-the-counter and prescription antiperspirants. Then there is onabotulinumtoxinA (Botox). In Canada, Health Canada approved onabotulinumtoxinA for sweating in 2001, so it has been used for more than a decade. It is quite effective, but not long-lasting.

Surgery is the third most common modality, but it is invasive. It involves making an incision, then an instrument is applied under the surface of the skin that attempts to destroy the sweat glands from underneath.

Medscape: Can you explain how the miraDry System works?

Dr. Lupin: The miraDry System uses microwaves locally applied to the underarm area. It destroys the sweat glands by heating the interface where they are located, the hyperdermal interface. So it works by heating. It actually cools at the same time as it heats, so it protects the surface of the skin. Therefore, it's a completely noninvasive device.

Medscape: Could you tell us about the study and what you found after 18 months of follow-up?

Dr. Lupin: There was a study in the United States looking at an earlier generation of this microwave device. The point of our study was 2-fold — one was safety and the second was efficacy. The previous study was 12 month; our study so far is at 18 months, but we plan to go to 2 years.

We had 31 patients from 3 different centers in Canada. The median age was 33 years; the age range was 18 to 65 years. There were 23 women and 8 men. We looked at the amount of sweating by weighing the sweat with grammametrics testing. Patients had to have at least 50 mg over 5 minutes. The baseline average for the 31 patients was 187 mg over 5 minutes.

We looked at subjective and objective criteria. Objectively, we measured the sweat, and patients had to self-report the severity of their sweating according to an established scale, called the Hyperhidrosis Disease Severity Scale (HDSS).

We used injectable lidocaine for local anesthesia to both underarm areas and then we treated them with several pulses of the microwave energy on each underarm. Every 30 days we would evaluate the effectiveness and safety.

Patients ended up having 2 or 3 treatments in total; we would wait at least 2 to 3 months before we would do subsequent treatment. The average number of treatments was 2 to get the best result.

The approved device now in the United States is a generation-4 device. We have a generation-3 device; they've actually made it even safer. Two treatments 3 months apart is now the recommendation.

We found that the gravimetric reduction, that is the total amount of sweat that they have at 12 months, was 84% less. We also looked at well-established index called the Dermatology Life Quality Index (DLQI), a 10-point questionnaire rated from 0 to 30, where 30 is severe and affects people's quality of life, and 0 is no impact.

The baseline DLQI score was 11.8; after 12 months, it was 1.9, so it had a significant impact on the patients' quality of life.

We also did a general patient satisfaction with the procedure; on average, it was about 90%.

The fourth and final thing was the HDSS — a scale from 1 to 4 (4 is severe, 1 is mild). It is really a scale that shows how much this problem bothers people on a daily basis.

All patients had to be 3 or 4 to begin with; at the end of 12 months, 100% of patients were 1 or 2, which was our goal.

The interesting thing about the 18 months is that the results at 1 month persisted to 18 months. We saw that results in all measures — patient satisfaction, the amount of sweating, HDSS score, DLQI score — at 1 month were almost the same as they were at 18 months.

So it works quickly and it persists at least 18 months.

Medscape: Were there any adverse effects from the treatment?

Dr. Lupin: As with any medical procedure, there are always some side effects. There is no medical procedure that doesn't have something, so some patients had transient redness — that was expected. There was some soreness and tenderness in the area that could last for 2 to 3 weeks, and some patients had swelling in the underarm area...which ranged from 1 week to 8 weeks.

Unexpectedly, about one third of patients found that they had less hair in the underarms, and two thirds found that they had less odor, because the other glands in the underarms that produce odor were affected by treatment, so we had a "hat trick" — reduced sweating, reduction of hair, and some reduction of odor.

Medscape: What can doctors tell their patients now about this treatment?

Dr. Lupin: Now we can say that there are 4 approved treatments for axillary hyperhidrosis. There are prescription antiperspirants, there is onabotulinumtoxinA, there is surgery, and now there is miraDry. We can tell patients that it is long-lasting and it is most likely permanent, because it doesn't just put the sweat glands to sleep, it actually removes the sweat glands, and we know that sweat glands can't regenerate. There is no reason the sweat should ever come back, so we can tell them it's a long-lasting noninvasive option — in fact, the longest-lasting noninvasive option.

Medscape: Can ablating the sweat glands under the arm be harmful?

Dr. Lupin: We have the same question when we use onabotulinumtoxinA. The simple answer is it's no more harmful than using an antiperspirant. It's not removing enough sweat that it will affect temperature regulation or cause heavy sweating somewhere else. The nice thing about it is that it is just a local effect. Think of it as doing what an antiperspirant would do but doing it most likely permanently and more effectively.

The study was funded by Miramar Labs. Dr. Lupin reports a financial relationship with Miramar Labs.

American Society for Laser Medicine & Surgery (ASLMS) 2012 Annual Meeting. Presented April 18, 2012.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: