Hyperhydrosis happens when you sweat a lot and there’s no obvious reason why. You may find that you sweat so much that perspiration drops off your body or soaks through your clothes. This can happen even if you aren’t overheated and haven’t exercised recently.

There are two types of hyperhidrosis you can be diagnosed with: primary and secondary. Primary hyperhidrosis occurs without another, underlying medical cause. Secondary hyperhidrosis is caused by other things, such as a medical condition or medication. Here are some of the more specific causes of hyperhidrosis.

1. Overreactive Nerves

Scientists don’t know exactly what causes primary hyperhidrosis symptoms, but they believe it has to do with nerves sending the wrong signals to your sweat glands. These signals tell your body to sweat when you don’t need to. The nerves may be overreacting, or they may simply be faulty. In some cases, this type of hyperhidrosis may have a genetic (inherited) component.

2. Certain Medications

Some medications may cause secondary hyperhidrosis. Not everyone who takes a certain drug will experience these kinds of side effects. Medicines that can cause excessive sweating include some pain relievers, diabetes drugs, antidepressants, hormonal medications, antibiotics, and antivirals. Not every medication in these classes can cause sweating.

If you’re on a new medication and suddenly start sweating more than usual, talk to your doctor or your dermatology team about possible side effects. Let them know about any herbal supplements you’re taking, as well as over-the-counter drugs. These may also cause hyperhidrosis.

3. Endocrine Conditions

Hyperhidrosis can also be caused by certain conditions that affect your endocrine system. That’s the system that creates and distributes hormones in your body. Both diabetes and thyroid problems may cause you to sweat a lot when they aren’t under control.

If you’ve been diagnosed with one of these conditions and start sweating heavily, talk to your endocrinologist. If you haven’t been diagnosed, your dermatologist may test you for these issues.

4. Certain Infections

You may also experience hyperhidrosis if your body is fighting an infection. Most of the time, you’ll also have other symptoms of an infection, depending on what kind of infection it is and what areas of the body are affected. But if you let your doctor know about your excessive sweating, they will probably want to check you for infections, just to make sure.

5. Hormonal Changes

When your sex hormones fluctuate, you may sweat a lot. This is most common with menopause, where people experience hot flashes that seem to happen at random. A doctor can check your hormone levels to see if they are causing your hyperhidrosis.

6. Other Chronic Medical Conditions

Some medical conditions can cause hyperhidrosis. Not everyone with these conditions will sweat excessively, but they can be a factor:

• Rheumatoid arthritis
• Heart failure
• Stroke

If you have one of these conditions and notice heavy sweating, talk with your doctor right away.

7. Neurological Disorders

In rare cases, disorders that affect your nervous system (neurological disorders) can cause hyperhidrosis. These disorders may change the way your nerves tell your body when it needs to sweat. This is not common, but it can happen. Parkinson’s disease is one of the most common nervous system disorders that can lead to sweating.

8. Certain Cancers

Some types of cancer can cause heavy sweating. As with neurological disorders, this is very rare. If you’re worried about cancer, talk to your doctor about your personal risk and whether you need to be screened.

Other Things You Need To Know About Hyperhidrosis

Hyperhidrosis doesn’t always happen together with stress, exercise, or exposure to heat. But these things can make you sweat even more. If you’re experiencing hyperhidrosis, you may want to avoid these until the episode has passed.

Sweating a lot suddenly can mean that you’re experiencing a serious medical event. If you have any of the following symptoms along with heavy sweating, get medical help right away:

• Cold skin
• Dizziness
• A fast heartbeat
• Pain in your throat, arms, chest, shoulders, or jaw

You should also see a doctor if you suddenly start sweating at night (night sweats). Contact a doctor if:

• You experience hyperhidrosis out of the blue when you haven’t experienced it before.
• You’re withdrawing socially because of sweating.
• Sweating is affecting your daily life and routine.

Your healthcare provider can help you get the diagnosis and treatment options you need.

Talk With Others Who Understand

On MyHyperhidrosisTeam, people share their experiences with hyperhidrosis, get advice, and find support from others who understand.

What do you and your healthcare provider think is causing your hyperhidrosis? Let others know in the comments below.