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?
Dear Reader: Hyperhidrosis is a disorder in which the sweat glands become overactive. The result is excessive perspiration that is not associated with exercise, temperature or any other typical triggers. Parts of the body that are commonly affected include the palms of the hands, armpits, soles of the feet, chest, the head and face. This last type of excessive sweating is known as craniofacial hyperhidrosis.
For the majority of people, hyperhidrosis does not pose a serious health threat. However, it can be uncomfortable and embarrassing, and it can interfere with quality of life.
Excessive sweating linked to a known cause, such as menopause, Parkinson’s disease, low blood sugar or an overactive thyroid gland is known as secondary hyperhidrosis. When it arises with no clear cause, it is known as primary hyperhidrosis.
The reason this disorder occurs is not fully understood. However, it is believed to be linked to a glitch in the workings of the sympathetic nervous system, which oversees the body’s fight-or-flight response and acts as its thermostat. Genetics may also play a role. It appears that when someone has primary hyperhidrosis, the brain is sending signals that activate the sweat glands, even though the conditions that would require the cooling effects of sweat are not present.
When it comes to managing the disorder, the antiperspirant your internist recommended is a common first-line approach. So are medications known as anticholinergics, which interfere with the electrical signals the body uses to activate the sweat glands. Beta blockers, which are medications that mask the physical manifestations of anxiety, are also sometimes prescribed. In some cases, patients opt for an endoscopic surgery called thoracic sympathectomy, in which certain nerves associated with sweating are severed.
Nerve impulses associated with sweating can also be muted with the use of Botox. That’s the product name for an injectable protein made from Botulinum toxin, which is a neurotoxin. Botox injections have come to be widely used in managing primary hyperhidrosis when topical treatments have failed. The treatment works by blocking the nerve signals that instruct the sweat glands to become active. It takes three to four days for the results of Botox injections for hyperhidrosis to become evident. Depending on each person, as well as the area beating treated, the results last for up to six months.
According to the International Hyperhidrosis Society, people who receive Botox injections have found excessive sweating decreases by more than 85%. Side effects of the treatment can include pain, swelling and bruising at the injection site. Although Botox is widely used for many types of hyperhidrosis, at this time, it has been FDA approved only for excessive underarm sweating. When used for other areas of the body, it is an off-label use.
With the failure of the antiperspirant to bring you relief, your internist can advise you on whether oral medications, Botox injections or surgery may be an appropriate next step.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
