If a whiff of your armpits after that last workout made you run to the shower, you’re not alone. Body odor due to sweating is common when you exercise, feel nervous, or are too warm. But certain medical conditions can also cause body odor.
Bad breath, smelly urine, and a strong body odor affect your aroma and may cause embarrassment. They also carry clues of a possible underlying health problem.
A sweet, fruity, acetone-like breath may be a sign of diabetic ketoacidosis (DKA), a serious medical condition.
Sweat or breath that smells like bleach or ammonia may point to liver or kidney disease.
Persistent foul breath may indicate gum disease or a lung infection.
Talk to your healthcare provider if you notice a sudden change in body odor, an increase in sweating, or have any other concerning symptoms.
What causes body odor?
Body odor occurs primarily when bacteria come in contact with your sweat. Human sweat by itself doesn’t have an odor. What you smell is the mixture of bacteria on your skin and sweat. The medical term for foul-smelling body odor caused by sweat is bromhidrosis.
Your body has two different types of sweat glands:
1. Eccrine glands
They are found almost everywhere on your skin. When your body’s temperature rises, your eccrine glands release water (sweat) to the skin's surface. As the sweat evaporates, this helps cool your skin and regulate your body temperature.
2. Apocrine glands
These glands are usually in areas where you have hair, like the armpits and groin. They start to function at puberty. Unlike eccrine glands, they produce a thicker, odorless fluid that contains protein.
Apocrine glands are the culprit for body odor. The thick fluid released by the apocrine glands is odorless but may develop a strong smell when combined with bacteria on your skin. This explains why you’re likely to have an unpleasant smell in your underarms and groin area when you sweat.
But body odor is not limited to smelly underarms or groins. Volatile organic compounds (VOCs) are chemicals emitted from the breakdown of other chemical compounds. Certain diseases cause VOCs to be released. These VOCs can be detected in the breath, urine, skin, and blood.
What medical conditions cause body odor?
Several factors, including gender and genetics, can influence how you smell. Your skin microbiome – the bacteria, viruses, and fungi that naturally live on your skin – plays a significant role, too. Poor hygiene, certain foods, hormones, or medications can cause body odor.
While deodorants and perfumes can mask an unpleasant scent, body odor can also give clues to possible medical conditions:
Among other functions, the kidneys are essential to eliminate the body’s toxins and waste through the urine. The protein you eat is broken down in the body and creates a toxic product called ammonia. Ammonia is then converted into a less toxic waste called urea which is typically eliminated when you pee. If your kidneys are not working properly, you may not be able to get rid of urea. A build-up of urea in your body – uremia – is a dangerous condition that can cause your breath and sweat to smell like ammonia or bleach.
The smell of ammonia or a urine-like smell on your breath may also be a sign that your liver is not working well enough. The liver performs important functions, including making bile to help digest food and ridding your body of harmful substances.
Having diabetes does not cause a body odor. But a complication of diabetes – called diabetic ketoacidosis (DKA) – can trigger a noticeable scent. DKA is a serious medical condition that occurs when your body lacks insulin. Your body starts to burn fat instead of glucose to get energy. DKA can cause your breath to have a fruity, sweet smell. Some associate the smell with rotten apples or nail polish remover.
Lung or oral problems
While it’s normal to have bad breath (halitosis) when you wake up, foul-smelling breath that doesn’t go away even after brushing your teeth may indicate a health problem. For example, pneumonia – a type of lung infection – can cause your saliva and breath to have a foul odor. Tuberculosis can also make your breath noticeably foul. Halitosis can also be a sign of gum disease or a throat infection.
A blockage in your small or large intestines can prevent the passage of some food material or liquids. A complete blockage is a serious, life-threatening condition that can cause your intestines to rupture if untreated. In some cases, the content in your intestines (poop) can back up into your stomach. Your breath may smell like feces, especially if you vomit.
Urinary tract problems
Bacteria that enter your urinary tract can cause problems like a urinary tract infection (UTI). In addition to cloudy urine, pain, or burning when you pee, you may notice a strong, foul-smelling odor in your urine.
An overgrowth of the bacteria naturally found in the vagina can cause bacterial vaginosis. You may experience vaginal discharge with a foul, fishy odor with this type of infection.
Other causes of body odor
Poop that smells worse than normal may be a sign of an infection in your small intestine, like Giardiasis. A bacterial infection in your underarm hairs – trichomycosis – can cause sweaty and smelly armpits and hair loss in the area.
This rare genetic disorder occurs when the body cannot break down a chemical compound called trimethylamine (TMA). TMA is found in certain foods. Excess TMA in the body causes a foul, rotten, fish-like odor in your breath, urine, or sweat.
Hyperhidrosis is a condition that causes you to sweat a lot even when the temperature is cool. If you have hyperhidrosis, you may develop body odor if the sweat comes in contact with bacteria on your skin. An overactive thyroid, or hyperthyroidism, may cause excessive sweating, which can lead to body odor.
Certain toxins may impact your body odor. Researchers found that people who ingested arsenic had a garlic-like body odor. Cyanide ingestion caused breath that smelled like bitter almond. And if your urine smells like violets, you may have ingested turpentine.
Some people sweat a lot on their feet which can cause a stinky odor. This is common, and the smell may go away after your wash and dry your feet. But, having sweaty feet may increase your risk of getting athlete’s foot, a contagious fungal infection of the skin of the feet.
Menstruation, menopause, and pregnancy cause hormone fluctuation. These hormone changes, including hot flashes and night sweats, may change your body odor.
Yes, the food you eat can lead to body odor. You may already know that eating asparagus can cause a strong urine odor, and excessive amounts of alcohol can be detected in your breath and skin pores. Some spices, like curry or cumin, tend to linger on your breath for a long time. Foods rich in sulfur – like garlic, onion, cabbage, broccoli, and red meat – break down into gases that can cause bad breath for hours after a meal.
When should I see a doctor?
Some types of body odor are temporary. Better hygiene or a healthier lifestyle may get rid of them. However, you should seek medical treatment if:
- You have a sudden change in your body odor.
- The body odor doesn’t go away.
- You have a fruity, sweet breath or body odor which may be a sign of DKA.
- Your body odor smells like ammonia or bleach, which could indicate liver or kidney disease.
- You sweat a lot even if you’re not physically active or are in a cool room.
- You notice other symptoms like pain, swelling, and bleeding with the foul odor.
- You think the odor may be related to poisoning.
- Your breath smells like poop.
- You think you have a UTI or a vaginal infection.
Everyone has their unique natural body odor. Some body odor can cause social embarrassment and have a negative effect on your quality of life, but there are many ways to get rid of body odor or reduce that unpleasant smell. It’s important to remember that some types of body odor, however, may be an indication of a serious medical condition.
- International Journal of Trichology. Trichomycosis (trichobacteriosis): clinical and microbiological experience with 56 cases.
- Centers for Disease Control and Prevention. Bacterial Vaginosis - CDC Basic Fact Sheet.
- National Library of Medicine. Anatomy, Skin Sweat Glands.
- International Journal of Molecular Sciences. Microbiota and Malodor - Etiology and Management.
- The Journal of Biochemistry. The scent of disease: volatile organic compounds of the human body related to disease and disorder.