What is the cause of Hyperhydrosis (Excessive Sweating)?
For some people, there may be no explainable cause for their excessive sweating, and they may be considered to have a medical condition known as essential (idiopathic or primary) hyperhydrosis. This may be due to over activity of the nerves that send signals to the sweat glands in the skin, the sympathetic nervous system.
Sometimes this idiopathic form of hyperhydrosis can be genetically transmitted, and it often runs in families. This form may first show up in early childhood or adolescence. Other people may have sweating as a symptom of known medical conditions, such as an overactive thyroid gland (hyperthyroidism), from nerve damage due to diabetes, psychiatric disorders such as panic attacks or anxiety disorders, or even due to the hot flashes associated with menopause.
Some medications may by themselves be the cause excessive sweating, such as the medications often used for prostate cancer, AIDS, or pyridostigmine (Mestinon™) used for the condition myasthenia gravis.
Why do I sweat?
Sweating is a normal bodily function that serves to cool off the skin and lubricate the skin (especially in areas that may rub against other areas of skin, such as the armpits, under the breasts, and between the legs). Special microscopic glands (sweat glands) in the deep layer of the skin make sweat by filtering fluid and salts out of the blood, and secreting this fluid up through small tubes in the skin. The sweat ducts, empty out into small pores at the top layer of the skin, the stratum corneum. Some areas of the skin have many sweat glands, while other areas have relatively few. They are present in the highest concentration on the palms of the hands and soles of the feet.
In addition to sweat glands, skin also has oil glands that surround almost every hair root, called sebaceous glands. Finally, some areas, such as the underarm and the groin, have special, unusual sweat glands called apocrine glands. Apocrine glands secrete a very thick type of sweat that has a large amount of fatty chemicals in it. These chemicals can be broken down by bacteria on the surface of the skin to create body odor.
Two different sets of nerves supply these many glands, the sympathetic nerves, which tend to increase sweating when one is excited, nervous, or afraid (the “fight or flight response”), and the parasympathetic nerves, which tend to decrease sweating of the skin. At the ends of the nerves, the body releases special chemicals called neurotransmitters, which carry the electrical signal from the nerves onto the cells near the nerve endings. For the sweat glands, the chemical at the tips of the sympathetic nerves is acetylcholine; too much of this chemical present next to the sweat glands stimulates them to produce large amounts of fluid. Many doctors feel that one of the biggest problems in people with idiopathic hyperhydrosis is the fact that the sympathetic nerves are over stimulated, making the neurotransmitters “go haywire” at the nerve endings. Many activities that stimulate the nervous system, such as strong smells, spicy foods, increased air temperature, exercise, high emotional excitement, stress or nervousness may cause attacks of excessive sweating through sympathetic nerve over activity.
How is hyperhydrosis treated?
Generally speaking, in order to decrease sweating the options are to decrease the nerve impulses to the sweat glands, decrease the acetylcholine, destroy the glands, or block off their ducts, so that the sweat cannot flow out onto the skin.
The following are the six main ways to treat hyperhydrosis:
1. One main way to cut down sweating is to use a solution on the surface of the skin to decrease sweat. These solutions usually contain aluminum metal salts, such as aluminum chloride, which have to be frequently reapplied, or else sweating increases again. This chemical is found in low concentrations in over the counter antiperspirants, but Dr. Jennifer Janiga can prescribe a prescription strength antiperspirant for you to try.
2. The sweat glands themselves can be destroyed, but since they are so small and numerous, and are located deep in the skin, methods such as electrolysis (which uses electric currents to destroy the hair roots) are not very practical. If only an isolated area of the skin, such as the underarms, causes sweating problems, procedures such as liposuction can reportedly remove the sweat glands located there. Dr. Janiga will refer you to a plastic surgeon if she thinks that this is a treatment option for you.
3. Electric currents through the skin, iontophoresis, may disrupt the function of the sweat glands, preventing them from working for a long time. With the use of a home operated machine, a small electric current is sent through the skin from one area to another. The electric current “shocks” the sweat glands and they stop making sweat until they recover. By using this machine regularly, a few times a week, prolonged dryness in the area of treatment can be achieved and last for weeks. This may work well if only the hands and feet have excessive sweating problem, but frequent treatments will be required.
4. Cutting or destroying the sympathetic nerves can interrupt the nerve supply to the sweat glands. Since these nerves are extremely small, they are usually reached near the spinal cord, where many nerves run together into structures known as sympathetic ganglia, before they spread out throughout the body. Once the nerves are cut or destroyed, the sweat glands that are supplied by those nerves stop secreting sweat. This may also cause other parts of the skin to lose their sympathetic nerve supply, so the skin may lose its ability to control its temperature and blood flow. This procedure is performed by a surgeon in an operating room. If Dr. Janiga thinks this option is right for you, she will refer you to a surgeon for evaluation.
5. Medication may be taken internally that works to block the neurotransmitter, acetylcholine, from stimulating the sweat glands. Some of the more useful medications include the anticholinergics (such as glycopyrrolate or atropine), some antihistamines, some antidepressants, and some of the tranquilizers. However, these medications will also affect other parts of the body, and may lead to side effects, including dry mouth, drying of other secretions, constipation, or other side effects.
6. One new approach that often works on small areas of skin that have excessive sweating is to inject botulinum toxin (Botox ®) into areas of the skin (such as the underarms). This treatment blocks the acetylcholine for up to a year before it wears off.
Do you treat Hyperhydrosis in your Reno/Tahoe office?
Yes. We evaluate and treat patients who are experiencing Hyperhydrosis. Appointment length varies and depends on severity of condition or other contributing factors, but is usually not more than 15-30 minutes.
For more information, or to set up a consultation with Dr. Jennifer Janiga for your Hyperhydrosis evaluation in our Reno dermatology office, please send us an email or call 775-398-4600.