What Causes Hyperhidrosis? | How to Treat It

All of us sweat. Any trip on public transportation in the summer will reveal this reality.

But while there are normal variations in the amount of sweat people produce, some of us — about 4.8% of the population, according to one study — suffer from a condition called hyperhidrosis, or “excessive sweating.”

Hyperhidrosis isn’t just your average physical response to being overheated. It involves sweating noticeably more than others and sweating in situations where you’re not even physically hot — think: calmly sitting or standing in a cool room. Not surprisingly, hyperhidrosis can cause discomfort, embarrassment and interfere with people’s’ professional, social and romantic lives.

Lance H. Brown, M.D., a surgical and cosmetic dermatologist, as well as a Mohs micrographic skin cancer surgeon based in New York City and East Hampton, explained that sweat is our body’s way of controlling body temperature by promoting heat loss through evaporation.

“Physical activity, hormones and stress can trigger our central nervous system to cause our body to produce sweat,” Brown said. “The amount we sweat is partially dependent on genetics and the number of sweat glands we have.”

Types of Hyperhidrosis

There are two types of hyperhidrosis: primary focal and secondary generalized. These categories were created to help medical professionals provide the proper treatment to patients. Distinguishing between primary hyperhidrosis and secondary generalized hyperhidrosis is crucial in understanding the basis of the condition.

Primary Hyperhidrosis

Primary hyperhidrosis is the type where excessive sweating is not caused by an underlying medical condition or side effect from a specific medication. In other words, excessive sweating is the actual medical condition and is not caused by a secondary condition.

With primary hyperhidrosis, specific areas of the body become sweaty, typically in focal areas such as the hands, feet, underarms, face and head. Most people suffering from hyperhidrosis experience this sweating in more than one area, and it usually happens symmetrically on both the left and right side of the body. This condition typically begins during childhood or adolescence, and begins with hands and feet.

Secondary Hyperhidrosis

Secondary generalized hyperhidrosis, on the other hand, is excessive sweating caused by a medical condition or a side effect of medication. Unlike primary focal hyperhidrosis, it usually starts in adulthood.

Terms for Different Parts of the Body

There are also different categorizations depending on where the excessive sweating is coming from:

• axillary hyperhidrosis: underarm sweating
• plantar hyperhidrosis: feet
• palmoplantar hyperhidrosis: hands and feet

Causes of Hyperhidrosis

Genetics

Hyperhidrosis typically ensues when a person has an excess number of sweat glands embedded in various parts of their bodies (most commonly: in their armpits, hands, and feet) or when their sweat glands are prone to hyperactivity.

Sweat glands, in addition to helping us cool down, also play a role in wound healing and skin regeneration. These versatile glands come in two kinds: eccrine and apocrine.

“Eccrine glands produce the majority of sweat,” Brown said. “They’re found on nearly our entire body but have the highest concentration on our palms, soles, armpits and forehead. Apocrine glands, by contrast, are primarily located in our armpits, groin and breast area, and produce secretions with different odors.”

Apocrine glands embedded in our outer ear canal also help produce ear wax. Individuals with hyperhidrosis usually have an excess or hyperactivity of eccrine glands.

Other Conditions, Medications or Drugs

In some cases, a disease, neurological disorder or the side effects of certain medications may be the culprit of excessive sweating (known as secondary generalized hyperhidrosis). Selective serotonin reuptake inhibitors [SSRIs] used to treat depression, such as bupropion (Wellbutrin), paroxetine (Paxil), fluoxetine (Prozac), citalopram (Celexa) and sertraline (Zoloft), tend to increase consumers’ propensities to sweat more than usual.

So do serotonin and norepinephrine reuptake inhibitors (SNRIs) like venlafaxine (Effexor) and tricyclic antidepressants like imipramine (Tofranil), nortriptyline (Pamelor) and amitriptyline (Elavil). Studies show that fluvoxamine (Luvox), an SSRI, and Trazodone (Desyrel), a heterocyclic antidepressant, are less likely to cause excess sweating.

Researchers believe SSRIs increase sweating either by altering signaling within the hypothalamus — a structure deep within the brain that helps regulate body temperature — or by altering serotonin signaling within the spinal cord (which can increase core body temperature). Tricyclics are assumed to increase sweating by inhibiting the reabsorption of a neurotransmitter and hormone called norepinephrine. More norepinephrine floating around in the brain and bloodstream may overstimulate the sympathetic nervous system that governs the stress response and makes us sweat.

Opioids such as morphine, hydrocodone, and Dilaudid stimulate cells (called mast cells) within the body that control the production of sweat, leading to increased perspiration in those who take these drugs.

Pilocarpine, which is used to treat glaucoma (an eye disease involving the buildup of fluid that damages the optic nerve and can lead to blindness) raises consumers’ risks of hyperhidrosis. Latanoprost eye drops, which are also used to treat glaucoma, increase the risk as well.

Does More Sweat Mean More Smell?

All that extra sweat, however, doesn’t necessarily amount to excess body odor.

“Body odor is caused by the odoriferous compounds resulting from microbial degradation of certain substances released by the apocrine glands,” explained Doris Hexsel, M.D., Medical Director of Hexsel Dermatology Clinics in Rio de Janeiro and Porto Alegre, Brazil. “Patients with axillary hyperhidrosis [excessive sweating under the arms] rarely have excessive body odor, possibly because the excessive sweating ‘washes’ the skin.”

The funk factor of certain bodily areas depends on whether they’re properly ventilated. Hexsel noted that feet, groins, and armpits secured beneath several layers of clothing may be prone to more odor, as a lack of ventilation creates a moist environment favorable to bacterial growth. This bacteria, she added, can generate foul smells as they metabolize excess sweat.

Excess sweat can also exacerbate certain skin conditions caused by fungus, like Athlete’s foot (tinea pedis) and jock itch (tinea cruris) — all forms of ringworm. Because skin that’s constantly moist may lead to skin breakdown, people who suffer from hyperhidrosis are also at an increased risk of bacterial and viral infection, such as the development of warts.

Luckily folks suffering from hyperhidrosis can take advantage of several treatments found to minimize symptoms. These solutions include topical treatments, dietary interventions and surgery.

Treatments for Hyperhidrosis

Aluminum Chloride

Aluminum chloride, the active ingredient in many antiperspirants, essentially plugs up sweat glands, Brown explained. Aluminum chloride hexahydrate is a heavier duty chemical composition that achieves a stronger effect. Antiperspirant deodorants are especially useful for people with axillary hyperhidrosis.

While this treatment may seem effective, Brown cautioned that aluminum-based antiperspirants products can cause skin irritation in some individuals. Additionally, some research suggests a link between aluminum-based products and cancer — though consistent evidence confirming this link has not been demonstrated.

Diet

Some foods, beverages and condiments raise our core temperature or trick our body into thinking our temperature is increasing, resulting in a stronger sweat response launched to regulate this uptick. These so-called “thermo-genic” consumables include legumes, salt, pepper, garlic, ginger, read meat, milk products, strawberries and cola-based soft drinks.

Spicy foods that contain a molecule called capsaicin also have this effect, as do caffeine and alcohol. Reduce your intake of these items if you’re looking to control how much you sweat, Brown advised.

Acupuncture

While no large-scale studies have yet been conducted to examine the efficacy of acupuncture, several case studies suggest acupuncture can reduce hyperhidrosis symptoms.

Iontophoresis

Used since the 1940s primarily to treat excessive sweating on the hands and feet, iontophoresis involves exposing areas of the body prone to hyperhidrosis to an ionized current. Iontophoresis can reduce the severity of hyperhidrosis in specific body areas, even if it requires repeated treatments.

Its mechanisms aren’t fully understood, but clinicians believe iontophoresis reduces sweating by thickening the outer layer of the skin. This modification has the effect of blocking sweat flow, disrupting normal nerve transmission (thereby interfering with sweat ducts’ functioning) and altering the acidity (pH level) of the sweat gland so less sweat is produced.

Side effects are minimal but include mild electric shock (if iontophoresis devices are not used correctly) and minor skin irritations. Iontophoresis is not advisable for individuals who have joint replacements, pacemakers, heart conditions, epilepsy, or for individuals who may be pregnant.

Botulinum Toxin (Botox)

Botulinum toxin injections are used to block the chemical messenger that leads to sweat and essentially makes sweating difficult at the area where it has been injected.

While this treatment option is not generally a first choice, it can be quite effective. When used to treat excessive underarm sweating, Botulinum toxin injections has proven to result in 82-87% decrease in sweating.

One treatment can last six to eight months. Be careful, though: Side effects can include flu-like symptoms in individuals with more sensitive immune systems, as well as weakness or numbness in the area of injection.

Surgery (Suction-Curettage and Sympathectomy)

When other treatments fail to succeed, some doctors recommend surgical removal of certain sweat glands, a process called suction-curettage. Blood clotting and swelling, fluid buildup at the site of surgery and death of surrounding tissues can occur as side effects of this approach.

At the more extreme end of surgical approaches to treat hyperhidrosis is endoscopic thoracic sympathectomy [ETS]. The sympathectomy procedure involves surgical destruction of a portion of the sympathetic nervous system involved in sweat gland signalling.

Unfortunately, this latter process can cause the body to overcompensate and produce even more sweat. Plus, sympathectomy risks causing nerve damage and, in rare instances, can cause a condition called Horner’s syndrome, which results from nerve disruption and manifests as drooping eyelids and decreased pupil size.

Medications to Treat Hyperhidrosis

Sometimes doctors will prescribe daily or as-needed medication to control excess sweating. Below are some commonly used prescription and over-the-counter drugs that help combat hyperhidrosis.

Anticholinergics

Anticholinergics reduce the activity of aceytlcholine, a neurotransmitter involved in learning, attention, arousal and movement, as well as the stimulation of sweat glands. Because of acetylcholine’s many functions, however, manipulating its concentrations may have unwanted effects on the brain and body.

In older adults, long-term anticholinergic consumption has been linked to an increased risk of dementia and brain atrophy, for example. Anticholinergics include glycopyrrolate (Robinul), oxybutynin (Ditropan), benztropine, and propantheline. Other side effects include dry mouth, constipation, blurry vision and an increased heart rate, as well as confusion, difficulty concentrating and difficulty remembering things.

Anti-Anxiety Medication

From beta blockers to benzodiazepines, some doctors prescribe anti-anxiety medications to manage underlying symptoms of stress, fear and worry that trigger sweat production (via activation of the sympathetic nervous system). By reducing emotional influences known to cue the nervous system into high arousal and, as a result, trigger excess sweating, many individuals will experience drier underarms and palms merely because they are calmer.

Benzodiazepines (such as alprazolam/Xanax, lorazepam/Ativan, chlordiazepoxide/Librium, and clonazepam/Klonopin) are addictive, however, and are not recommended as a first line of treatment. These types of medications also come with side effects such as drowsiness, impaired memory and concentration and, in some cases, exacerbation of depressive symptoms.

Beta-blockers (like propranolol/Inderal, atenolol/Tenormin, and nadolol/Corgard) are also used to manage anxiety. The problem is they lower blood pressure and can increase fatigue and weight gain while also making consumers’ hands and feet colder.

Meet Before You Treat

If you’re concerned about how much you sweat, talk to your doctor before beginning any treatment regimen. He or she will guide you on what options exist and which approaches might work best for you. For even more information about hyperhidrosis, take a look at the International Hyperhidrosis Society’s website.