Normal sweating helps to keep the body temperature steady in hot weather, during a high temperature (fever), or when exercising. Excessive sweating (hyperhidrosis) means that you sweat much more than normal. Even when you are not hot, anxious, or exercising, you make a lot of sweat.
Excessive sweating is classified into three types (as follows). It is important to know which type you have, as the causes and treatments are very different.
Hyperhidrosis, or excessive sweating, is a common disorder that produces a lot of unhappiness. An small percentage of Americans suffer from excessive sweating of the underarms (axillary hyperhidrosis) or of the palms and soles of the feet (palmoplantar hyperhidrosis).
Underarm problems tend to start around puberty, while palm and sole sweating may begin earlier, often during childhood. Untreated, these problems may continue throughout life.
Sweating is embarrassing, staining clothes, and it complicating business and social interactions. Severe cases can have serious practical consequences, like making it difficult to hold a pen, grip a steering wheel, or shake hands.
What is the cause of hyperhidrosis?
Although neurologic, metabolic, and other systemic diseases can sometimes cause excessive sweating, most cases occur in people who are otherwise healthy.
Heat and emotions may trigger hyperhidrosis in some, but many who suffer from hyperhidrosis perspire nearly all the time, regardless of their mood or the weather.
Primary (idiopathic) focal hyperhidrosis
This means that excessive sweating occurs in one or more of the following focal places: palms of the hands; soles of the feet; armpits (axillae); face/scalp.
You sweat normally on the rest of the body. It tends to be symmetrical – that is, both palms, both feet, both armpits, etc, are affected. The exact cause is not known and it is not associated with any other conditions. (The word idiopathic means of unknown cause.)
It just seems that the sweat glands in these areas are overactive or more sensitive than normal. In some people, it may run in the family so there may be some genetic factor involved in causing it. It usually first develops under the age of 25, but it can develop at any age.
Men and women are equally affected. It is common and affects about 3 in 100 people.
The severity can vary from time to time. It may come and go and can be made worse by triggers such as anxiety, emotion, spicy foods, and heat.
Anxiety about the sweating itself may make it worse. However, for most of the time, nothing obvious triggers the sweating. It tends to be a long-term condition, but symptoms improve in some cases over time.
If you have the typical symptoms of primary focal hyperhidrosis, you usually do not need any tests. Your doctor may suggest one or more treatments (below) if normal antiperspirants do not work well.
Secondary focal hyperhidrosis
This is uncommon. It means that the excessive sweating occurs in a particular focal part of the body. But, unlike primary focal hyperhidrosis, there is a known or likely cause.
For example, a spinal disease or injury may cause sweating in one leg. Any focal sweating that is not symmetrical (that is, just in one hand, or one leg, etc) may suggest a secondary cause rather than primary focal hyperhidrosis which is usually symmetrical. Your doctor may suggest some tests to look for an underlying cause if one is suspected.
This means that you sweat more than normal all over. This is less common than primary focal hyperhidrosis. However, it is usually caused by an underlying medical condition.
A whole range of conditions can cause a generalised increased sweating. For example:
- Anxiety disorders.
- Various heart problems.
- Damage to nerves in the spinal cord.
- Side-effects to certain medicines.
- Various hormonal problems (including an overactive thyroid gland).
- Certain cancers.
If you have generalised hyperhidrosis your doctor is likely to examine you and do some tests to find out the cause. Treatment depends on the cause.
The rest of this leaflet is only about primary focal hyperhidrosis.
What are the possible complications of primary focal hyperhidrosis?
Although not a medically serious condition, excessive sweating (hyperhidrosis) can be distressing and embarrassing. For example, if you have bad palm sweating you tend to have a cold, sweaty handshake and sweat may drip from your hands on to work documents, computer keyboards, etc.
If you have bad armpit sweating, you may become embarrassed by the frequent wet patch that develops on clothes under your arms. You may need to change clothes during the day. You may avoid social contact or avoid doing sports because of embarrassment about the condition.
Other complications are uncommon. In some cases, the affected skin can become sore, irritated and prone to infection. There is a risk of developing eczema on affected skin.
If you find that soaps irritate the affected skin, use a bland soap substitute such as a moisturiser (emollient) ointment or cream.
If possible, avoid triggers which can make things worse such as heat or spicy food.
If you have armpit sweating:
- Try using normal antiperspirants regularly. (Note: there is a difference between antiperspirants and deodorants. Antiperspirants reduce the release of sweat; deodorants mask any unpleasant smells.
- Avoid clothes that more easily show up sweat marks. As a rule, white and black coloured clothes are less noticeable when wet than other colours.
- Wear loose clothing under the armpits. Avoid clothes made with man-made fibres such as Lycra® and nylon.
- Consider using dress shields (also known as armpit or sweat shields) to absorb excess sweat and protect delicate or expensive clothing. These can be obtained via the internet or the Hyperhidrosis Support Group (contact details below).
- If you have excessive feet sweating, it can help to:
- Change your socks at least twice a day.
- Use an absorbent foot powder twice daily.
- Wear a different pair of shoes on alternate days. This allows them to dry fully.
- Avoid sport shoes or boots. These are often less breathable than normal shoes are, so are more likely to keep the sweat in.
- Aluminium chloride – a strong antiperspirant
If normal antiperspirants do not work, it is worth trying an antiperspirant that contains aluminium chloride. This is a strong antiperspirant. It is thought to work by blocking the openings of the sweat ducts. It tends to work best in the armpits. However, it may also work for sweating of the palms and soles.
Although it may also work on the face, some doctors do not recommend using this on the face, as it may cause severe eye irritation if it gets into an eye.
There are several brands of aluminium chloride-based antiperspirants. For example: Driclor® and Anhydrol Forte® come in a bottle with a roll-on applicator. ZeaSORB® is a dusting powder that contains aluminium chloride. You can buy these at pharmacies.
Some are also available on prescription. It is important to use aluminium chloride-based antiperspirants correctly. Read the instructions that come with the product you use. These usually include the following:
Apply to clean, dry skin. (It is more likely to cause irritation on wet or moist skin.) Therefore, wipe the skin dry with a towel or dry flannel before applying.
Some people use a hairdryer to make sure the skin is dry before applying.
Ideally, apply at night (bedtime) when the sweat glands are less likely to be as active.
- Wash it off the next morning.
- Do not shave the area 24 hours before or after use.
- Avoid getting it in the eyes, and do not apply on broken or inflamed skin.
- Some doctors do not recommend that you apply this treatment to your face.
- Apply every 24-48 hours until the condition improves. Then apply once every 1-3 weeks, depending on response. (It may take a few weeks to build up its effect. This is because it is thought to clog up the sweat gland gradually, which causes a gradual reduction in sweating.)
If successful, treatment can be continued indefinitely. You may only need to apply it once every 1-3 weeks to keep the sweating under control.
Note: aluminium chloride antiperspirants often cause skin irritation or inflammation. If this occurs, it is often still worth persevering if the irritation is tolerable, as the benefit may outweigh the irritation. To reduce the effects of any skin irritation or inflammation that may occur:
- Reduce frequency of use; and/or
- Apply a moisturiser (emollient) every day after applying the aluminium chloride; and/or
- Apply a short course of a mild steroid cream such as hydrocortisone 1% to the affected area twice daily for a maximum of 14 days. (Steroid creams reduce inflammation.)
Other treatments for primary focal hyperhidrosis
If the above general measures and antiperspirant treatments do not work, your doctor may suggest that they refer you to see a skin specialist (dermatologist). The specialist may suggest one of the following treatments.
This is a treatment that uses electrical stimulation. It is used mainly to treat sweating of the palms and/or soles. It can also be used to treat armpit sweating. It works well in most cases. Treatment involves putting the affected areas (usually hands and/or feet) into a small container filled with water.
A small electrical current is then passed through the water, from a special machine. It is not dangerous, but may cause some discomfort or a pins and needles feeling. The exact way this helps to treat sweating is not known. It may help to block the sweat glands in some way.
You will usually need 3-4 treatment sessions per week. Each treatment session lasts 20-40 minutes. Most people see an improvement after 6-10 sessions. A maintenance treatment is then usually required once every 1-4 weeks to keep symptoms away.
If the treatment does not work with tap water, a drug called glycopyrronium bromide is sometimes added to the water. This may improve the rate of success.
However, iontophoresis does not work in every case. Also, some people develop side-effects from the treatment, such as a dry or sore mouth and throat, and dizziness, for up to 24 hours after each treatment episode.
Until recently the downside to iontophoresis was that it required a trip to hospital for each treatment session. This can be time-consuming and impractical for some. However, modern machines are smaller and can now be bought for home use.
So, if you find that this treatment works for you, you may wish to consider buying a machine to use at home. However, you should take advice from the specialist who recommended iontophoresis for you before you buy a machine.
You should not have iontophoresis if you are pregnant, or have a metal implant, such as a pin to fix a bone break (fracture), or if you have a pacemaker.
Botulinum toxin injections
This is an option that usually works well for armpit sweating. Treatment consists of many small injections just under the skin in the affected areas. The botulinum toxin stops the nerves in the skin that control the sweat glands from working.
Botulinum toxin is not licensed to treat sweating of the palms and face. This is because there is a risk that the injections may stop some of the nearby small muscles of the hands or face from working.
The downside of botulinum toxin is that the effect usually wears off after 4-12 months. Therefore, to keep working, the treatment needs repeating when the effect wears off.
Some people get mild flu-like symptoms for a day or so after treatment. Also, the sites of the injections can be sore for a few days after treatment. A severe allergic reaction can (rarely) occur after an injection. It is also very expensive and not usually available on the NHS.
An operation is an option for people who have not been helped much by other treatments, or if other treatments cause unacceptable side-effects or problems.
For armpit sweating – an option is to remove the sweat glands in the armpit. There are various techniques. One technique is to remove the sweat glands from the underside of the skin through a small hole cut in the skin (called suction curettage).
A recent innovation has been to use a laser to destroy the sweat glands in the armpit – laser sweat ablation (LSA). This may result in less scarring than other surgical techniques. However, there have not been any studies looking at the long-term outcome with laser treatment.
For palm sweating – an option is to have an operation to cut some of the nerves that run down the side of the spinal cord. These nerves control the sweat glands in the hands.
The operation is called endoscopic thoracoscopic sympathectomy. It is done by keyhole surgery, using a special telescope to locate the nerve, and then to cut the nerve. Most people are pleased with the result of the operation.
However, a complication that may occur following this operation is a compensatory increase in sweating in other parts of the body (such as in the chest or groin). This can be worse than the original problem in the hands.
Before you undergo surgery, you should have a full discussion with the surgeon. He or she will explain the pros and cons of the different surgical techniques, chance of success (usually high), and possible risks and complications. For example, as with any other type of surgery, there is a small risk from the anaesthetic.
Also, wound infection and damage to other nearby structures, although uncommon, are other possible complications.
Surgery is not usually done for sweating of the soles. Although cutting the nerves next to the spinal cord in the lower back region may cure the problem of sweating, there is a high risk of this also affecting sexual function.