Ask the Doctors: Botox injections one way to treat excessive sweating

Dear Doctors: Several years ago, I began sweating on my forehead. It gradually became more profuse until my entire head was soaking wet. My internist diagnosed hyperhidrosis. An antiperspirant he suggested worked but only briefly. What is the cause of hyperhidrosis? Is there any treatment?

Answer: Hyperhidrosis is a disorder in which the sweat glands become overactive. The result is excessive perspiration that isn’t associated with exercise, temperature or other typical triggers.

Parts of the body affected include the palms, armpits, soles, chest, head and face.

Hyperhidrosis doesn’t usually pose a serious health threat. But it can be uncomfortable and embarrassing.

Excessive sweating with no clear cause is called primary hyperhidrosis. When it’s linked to a known cause — such as menopause, Parkinson’s disease, low blood sugar or an overactive thyroid — that’s secondary hyperhidrosis.

This disorder is believed to be linked to a glitch in the sympathetic nervous system, which oversees the body’s fight-or-flight response and acts as its thermostat. Genetics might play a role, too.

When someone has primary hyperhidrosis, it appears the brain sends signals that activate the sweat glands even though the conditions that would require the cooling effects of sweat aren’tpresent.

The antiperspirant your internist recommended is a common first-line approach to managing the disorder. So are anticholinergics medications, which interfere with the body’s electrical signals to activate the sweat glands. Beta blockers — which mask the physical manifestations of anxiety — sometimes are prescribed. In some cases, patients opt for an endoscopic surgery called thoracic sympathectomy in which nerves associated with sweating are severed.

Nerve impulses linked to sweating also can be muted with Botox, an injectable protein made from the Botulinum neurotoxin. Botox injections — widely used in managing primary hyperhidrosis when topical treatments have failed — block nerve signals that instruct sweat glands to become active. It takes three to four days for results, which last up to six months.

The International Hyperhidrosis Society says people who get Botox injections have seen excessive sweating decrease more than 85%.

Side effects can include pain, swelling and bruising at the injection site. Though Botox is widely used for many types of hyperhidrosis, it has been approved by the federal Food and Drug Administration only for excessive underarm sweating. For other areas of the body, it’s an “off-label” use.

With the antiperspirant failing to bring you relief, your internist can advise you whether oral medications, Botox or surgery is an appropriate next step.

Dr. Eve Glazier and Dr. Elizabeth Ko are internists at UCLA Health.