Sweating is your body’s way of cooling itself off. Some people are not able to sweat normally because their sweat glands are no longer functioning properly. This condition is known as hypohidrosis or anhidrosis. It can affect a person’s entire body, a single area, or scattered areas.
The inability to sweat normally can cause overheating, which can lead to heat stroke—a potentially fatal condition.
Hypohidrosis can be difficult to diagnose; mild hypohidrosis often goes unnoticed. The condition has many causes. It can be inherited or develop later in life.
As you age, a diminished ability to sweat is normal. Conditions that damage your autonomic nerves, such as diabetes, also make problems with your sweat glands more likely.
Skin disorders that inflame the skin can also affect your sweat glands. These include psoriasis, exfoliative dermatitis, heat rash, scleroderma, and ichthyosis. Some people inherit a damaged gene that causes them to have sweat gland problems or no sweat glands at all.
Any condition that causes nerve damage can disrupt the functioning of your sweat glands. This includes:
- Ross syndrome
- Parkinson’s disease
- multiple system atrophy
- Sjögren’s syndrome
- small cell lung cancer
- Fabry disease
- Horner syndrome
Skin damage from severe burns can permanently damage sweat glands. Other sources of damage include radiation, trauma, infection, and inflammation.
Taking certain medications, particularly those known as anticholinergics, can result in reduced sweating. These medications have side effects that include sore throat, dry mouth, and reduction in perspiration.
Some people may inherit a damaged gene that causes their sweat glands to malfunction. The inherited condition hypohidrotic ectodermal dysplasia causes people to be born with either very few or no sweat glands.
Note that heat stroke also causes a reduction in sweating.
Symptoms of hypohidrosis include:
- scant perspiration, even when other people are perspiring heavily
- muscle cramps or weakness
- flushed appearance
- feeling overly hot
Mild hypohidrosis may go unnoticed unless you engage in vigorous exercise and become overheated because you’re not perspiring normally.
Taking a thorough medical history is important for diagnosing this condition. You should share all symptoms that you’ve experienced with your physician. This includes breaking out in a red rash or skin flushing when you should be sweating. It’s important to tell him or her if you sweat in some parts of your body but not in others.
Your physician may use any of the following tests to confirm a diagnosis of hypohidrosis:
- axon reflex test: Small electrodes are used to stimulate your sweat glands. The volume of sweat produced is measured.
- silastic sweat imprint: measures size distribution of your perspiration
- thermoregulatory sweat test: Your body is coated with a powder that changes color in areas where you sweat. You enter a chamber that causes your body temperature to reach a level at which most people would sweat.
- skin biopsy: Some skin cells and perhaps some sweat glands are removed for examination under a microscope.
Hypohidrosis that affects only a small part of your body usually won’t cause problems and may not require treatment. If an underlying medical condition is causing hypohidrosis, your physician will treat that condition. That may reduce your symptoms.
If medications are causing your hypohidrosis, your physician may recommend trying another medication or reducing your dosage. While this is not always possible, adjusting medications may help to improve sweating.
It may not be possible to prevent hypohidrosis, but you can take steps to avoid serious illnesses related to overheating. Wear loose clothing and don’t overdress when it’s hot. Stay inside if possible, and take care not to overexert yourself when it’s hot.
You can also take steps to cool your body off and avoid overheating. This includes applying water or cool cloths to your skin to simulate sweating. When the water evaporates, you will feel cooler.
If left untreated, hypohidrosis can cause your body to overheat. Overheating requires quick treatment to prevent it from worsening into heat exhaustion or heat stroke. Heat stroke is a life-threatening condition that demands prompt emergency treatment.