Everyone has a unique body odor (BO), which can be pleasant or subtle, but when we think of BO, we usually think of an unpleasant smell.

Changes to body odor may be due to puberty, excessive sweating, or poor hygiene. Sudden changes are typically caused by the environment, medications, or foods that you eat.

However, body odor, especially sudden and persistent changes to your normal odor, can sometimes be a sign of an underlying condition.

A sudden change in body odor typically occurs in a specific area of the body. Common areas include the:

You may also notice a sudden smell from your stool, urine, earwax, or genital discharge. No matter the location, the odor can vary. It can be foul, pungent, fishy, sour, bitter, or even sweet.

Other symptoms you experience will depend on the cause. If the change in odor is due to infection, the smell may also be accompanied by:

  • redness
  • a rash
  • itching
  • oozing, discharge, or discoloration

Your environment, the things you eat, medications you take, shifts in hormone levels, or underlying disorders may all be behind a sudden change in body odor.

Changes in body odor can be a normal part of development, such as when an adolescent is going through puberty. During puberty, sweat glands and hormones become more active, which can cause BO.

If you’ve been working out, excessive sweat may be the culprit. If you don’t wear antiperspirant or practice healthy hygiene habits, sweat can mix with bacteria, causing an unpleasant smell.

If body odor is persistent and accompanied by other symptoms, it may be something else.

Diet

The foods you eat can sometimes cause a sudden, temporary change in body odor. For instance, many people experience a sudden, strong smell from their urine after eating asparagus. The smell will go away once the food is metabolized, unless it’s eaten daily.

Certain foods can also cause you to produce more gas, which may lead to belching or flatulence. Depending on the foods you eat, and how much gas you produce, this could create a foul smell.

Some foods that may cause smelly gas include:

  • broccoli
  • cauliflower
  • cabbage
  • bok choy
  • asparagus

If you have a food intolerance or sensitivity, the foods you’re sensitive to can also cause extra gas.

Your overall diet can also affect body odor. Some research has found that males who had a healthy diet high in fruits and vegetables had better-smelling sweat, no matter how much they sweat.

On the other hand, self-reports showed that high carb intake was associated with less pleasant smelling sweat.

Other research suggested that high meat consumption may have a negative effect on body odor, compared to a plant-based diet.

Bad breath can easily occur due to consuming certain foods, especially strong flavors such as spices, garlic, onions, or radish. Smoking tobacco products can also cause bad breath.

Stress

Stress and anxiety can occasionally cause you to sweat more, leading to a stronger body odor.

If you have hyperhidrosis disorder, you sweat excessively and uncontrollably, sometimes for no apparent reason. Some people develop this disorder due to genetics, an underlying health condition, or while taking certain medications.

According to 2016 research, hyperhidrosis and stress are connected. Many people who develop this condition experience stress, especially if the excess sweating affects their self-esteem or confidence.

Hyperhidrosis is often diagnosed in people with mental health conditions, such as social anxiety, which may influence its onset.

Diabetes (diabetic ketoacidosis)

Diabetes mellitus is a condition that occurs when your body either doesn’t make enough insulin, or can’t effectively use what it makes. It leads to high blood sugar.

If blood sugar levels get very high, a complication called diabetic ketoacidosis (DKA) can occur. Ketones build up to dangerous levels in the body and are secreted into the blood and urine. Additionally, DKA causes your breath to have a fruity odor.

Medical Emergency

If you have diabetes and experience a sudden fruity smell in your breath accompanied by frequent urination and a very high blood glucose level, see a doctor immediately. Diabetic ketoacidosis is a medical emergency.

Menopause, menstruation, and pregnancy

Have you ever thought you might smell different during your period? Research has found that women at high fertility within their menstrual cycle actually put out a different, perceived to be more attractive, scent to men than those at low fertility in their cycle.

This scent was even suggested to influence women’s interactions with other women, as fertility apparently smells good to everyone.

Other times, hormone fluctuations may cause a change in body odor or vaginal odor. This may not necessarily be unpleasant — just different. A subtle smell isn’t cause for concern, and instead may be due to pregnancy, menopause, or menstruation.

Vaginal infections

Several vaginal infections, such as a vaginal parasite infection or bacterial vaginosis, may cause a sudden change in vaginal odor. Other types of infections that occur outside of the vagina may also cause a change in body odor in the affected area.

Vaginal yeast infections usually don’t cause vaginal odor. However, they’re typically accompanied by itching, redness, or burning.

Bacterial vaginosis is the most common vaginal infection in women of childbearing age and often produces a fishy odor. Its other symptoms are similar to those of a yeast infection.

Trichomoniasis, a type of parasitic sexually transmitted infection, often has no symptoms but may change vaginal odor. Discharge can smell bad, change color, or become frothy.

Skin infections

If your skin develops an infection, either new or due to a preexisting condition, you may experience a sudden smell at the site of the infection.

Some types of skin infections or conditions that might cause a smell include:

  • trichomycosis axillaris, a bacterial infection of underarm hair follicles
  • erythrasma, a superficial bacterial skin infection
  • intertrigo, a rash in a skinfold that can become odorous in the presence of a superimposed, secondary infection such as candidiasis (yeast infection)

Athlete’s foot

If your feet are suddenly starting to smell bad and itch, you may have developed a common fungal infection called athlete’s foot.

Fungus thrives in the warm, moist environment of your shoes and socks. If you don’t practice healthy foot hygiene habits, you may be more likely to develop it.

Cancer

Can cancer smell? Some people with advanced cancer have reported unpleasant body odors, but they’re typically due to infected cancer-related wounds. These wounds occur in around 5 percent of people with cancer.

Some people with gynecological tumors do complain of unpleasant-smelling vaginal discharge. This results from certain acids that occur, which can be reduced by using the antibiotic metronidazole.

Vitamins or supplements

Vitamin and mineral deficiencies (when you don’t get enough vitamins or minerals in your diet) or malabsorption (when your body can’t absorb the nutrients in what you eat) can sometimes cause body odor, or a smell to occur in your stool or urine.

For instance, scurvy — vitamin C deficiency — can cause sweat to smell putrid.

Other causes

  • Urinary tract infection (UTI). A bacterial UTI occurs when bacteria enter your urinary tract and multiply. This type of infection can cause your urine to produce a strong odor, along with affecting the sensation, frequency, urgency, and appearance of your urine.
  • Pneumonia. This is a lung infection that sometimes causes foul-smelling breath and sputum.
  • Tuberculosis (TB). This is a bacterial infection that occurs in the lungs, throat, and neck, causing breath to have a foul smell. Swelling in ulcerated lymph nodes may also produce a smell of stale beer.
  • Toxin poisoning. If you ingest certain toxins, your body odor may be affected. For instance, ingesting cyanide can cause breath to smell like bitter almond. Arsenic and certain insecticides can create an intense garlic-like odor. Poisoning by turpentine makes urine smell like violets.
  • Uremia. This is a sign of kidney failure. It can cause breath to smell of ammonia or urine.
  • Intestinal obstructions. If intestines become obstructed, some people may vomit the contents of their stomach, causing them to have fecal-smelling breath.
  • Belly button infection. Although hygiene is usually the cause of a smelly navel, if your belly button starts to have an offensive smell, it may be infected. If infected, other symptoms may include discharge, redness, itchiness, swelling, and even bleeding.
  • Ear infection. While earwax is normal and healthy, smelly earwax may indicate a problem or infection. Other symptoms can include redness, itching, pain, balance issues, hearing issues, and pus.

Hyperhidrosis

If your hyperhidrosis is secondary to an underlying condition, treating that condition should help your symptoms. If it’s due to a certain medication, you may want to speak with a doctor about adjusting it.

If there’s an unknown cause, there are several treatments that may help:

  • prescription creams or antiperspirants
  • medications
  • seeing a mental health professional and practicing relaxation techniques
  • surgery
  • Botox injections

It can also help to make lifestyle changes where you bathe daily, choose clothing based on breathable, natural materials, and change socks often to let your feet get some air.

Infections

Although many types of infections aren’t serious, they should be handled promptly to avoid complications.

Infections will be treated differently depending on the cause and severity. Treatments are usually done with an antibiotic or antifungal agent. These are typically topical, but may be oral or intravenous as well.

Check out how to treat each of these infections:

Managing diabetes

If you have the symptoms of diabetic ketoacidosis where you experience fruity-smelling breath, you should seek emergency medical treatment.

Managing diabetes is all about adequately managing your blood glucose level. Check out the best ways to manage diabetes with medications, alternative treatments, or natural remedies.

Changing diet, supplements, or medications

If your body odor changes are due to foods, you may want to avoid them and increase variety in your diet.

If you have a vitamin deficiency, a doctor can find out with a simple blood test. You can get more of these vitamins by adding certain foods to your diet, or by taking supplements.

If a side effect of a medication you’re taking is causing your body odor to change in an unpleasant way, speak with a doctor. They can help you discuss your options, either adjusting your dose or switching to another medication.

Don’t stop taking any medication until you’ve spoken with a doctor.

Athlete’s foot

Athlete’s foot is usually very responsive to at-home treatments, including:

  • over-the-counter antifungal powders, sprays, ointments, and lotions
  • hydrogen peroxide or rubbing alcohol
  • oils such as tea tree or neem
  • talcum powder
  • sea salt baths

Cancer

Having cancer itself typically doesn’t smell, but having an infected wound related to it can.

If you experience a sudden change in body odor and have been diagnosed with cancer, speak with your doctor. They can treat the infected wound.

Some sudden changes in body odor can come down to increasing your healthy hygiene habits. Here are some tips to practice better hygiene:

  • Use antiperspirants or deodorants. You can use store-bought deodorants, more natural ones, or even make your own. Whatever you choose, these products can help manage your sweating and control body odor.
  • Take care of your feet. Ensure that your feet don’t stay in a damp environment for long. If your socks get damp, change them. For healthy feet, it can also help to make sure your shoes are the right fit and to use a pumice stone to reduce foot calluses.
  • Practice good oral hygiene. Brush your teeth and tongue. Dentists typically recommend brushing twice a day for two minutes at a time.
  • Gently cleanse sensitive areas. Sensitive areas may include your genital area, anus, and ears. Don’t douche, but use gentle cleansers to keep your genitals healthy. Gently rinse your ears with warm, not hot, water to help loosen earwax and clean your ear canal.
  • Create a shower routine that works for you. It’s up to personal preference how often you shower, but if you’re experiencing unwanted body odor, you may want to increase how often you bathe. Showering rinses away dead skin cells, dirt, bacteria, and oils.

If an adolescent is going through puberty, a change in body odor is completely normal. Encouraging the above healthy habits can help.

If the change in body odor is subtle and isn’t accompanied by worrisome symptoms, it may be due to hormone changes. You don’t need to treat this change unless it bothers you.

You should seek medical treatment if:

  • you have any change in odor accompanied by signs of infection
  • the smell may be related to toxin poisoning
  • you have been diagnosed with cancer
  • your diabetes is poorly managed, or you believe you may be experiencing diabetic ketoacidosis
  • the bad odor is accompanied by pain, bleeding, or other serious symptoms
  • the odor doesn’t go away

Sudden changes in body odor are often not a sign of anything serious. The easiest way to know if you should be concerned is how long the smell lasts, if it’s specifically related to something, or if it’s accompanied by other symptoms.

If the sudden smell has you worried and it persists, it never hurts to set up a doctor’s appointment or call a doctor or nurse for advice.