Body odour

Body odour, often called BO, is a smell coming from the skin, sweat, breath, or another part of the body. Sweat itself often has little smell. Odour usually develops when bacteria on the skin break down sweat and other secretions.

It is especially common in the armpits, groin, feet, and skin folds. Exercise, hot weather, stress, and hormonal changes can make it more noticeable.

Diet, medicines, excessive sweating, skin problems, and some illnesses can affect how you smell. Persistent unpleasant body odour is sometimes called bromhidrosis.

Body odour is usually something you or another person notices rather than a physical feeling. The smell may be musty, sour, strong, or different from your usual scent.

You may also notice:

• Damp clothing or visible sweat patches
• Foot odour that returns after changing socks
• Soft, irritated, or broken skin in damp folds
• Itching, redness, pain, or discharge
• A new smell from the breath, urine, vaginal area, or another specific site

Smell is subjective. Sometimes a person remains worried about odour even when others cannot detect it. Speak to a healthcare professional if this concern is affecting daily life.

Common causes include sweat mixing with normal skin bacteria. Apocrine glands, found mainly in the armpits and groin, produce secretions that bacteria can break down into odour-producing substances.

Exercise, heat, stress, puberty, menopause, and other hormonal changes can increase sweating. Tight or damp clothing may trap sweat, while shoes that do not dry fully can contribute to foot odour.

Garlic, onions, strong spices, alcohol, and smoking may temporarily affect body or breath odour. Some medicines can increase sweating or change the smell of sweat or breath. Do not stop a prescribed medicine on your own.

Less common causes include excessive sweating, known as hyperhidrosis, and skin conditions that allow bacteria or fungi to grow in damp areas. Dental disease, tonsil problems, or dry mouth may cause persistent breath odour.

Rare inherited conditions can affect how the body processes chemicals. For example, trimethylaminuria may cause a fish-like smell. Kidney, liver, or metabolic illnesses can also change odour, but smell alone cannot identify them.

Book a routine appointment if the odour is new and persistent, has no clear explanation, or does not improve with self-care. Arrange an assessment if sweating is excessive, occurs at night, disrupts daily activities, or has suddenly changed.

Seek same-day medical advice if odour occurs with:

• A painful, red, warm, or swollen area of skin
• Pus, spreading redness, or fever
• Strong vaginal odour with pelvic pain, fever, or unusual discharge
• A wound that smells unpleasant or is becoming more painful

Get emergency help for fruity or acetone-like breath with vomiting, stomach pain, deep or rapid breathing, severe drowsiness, or confusion. These can be signs of diabetic ketoacidosis, a dangerous build-up of acids in the blood. This is especially important if you have diabetes, but it can be the first sign of diabetes.

Difficulty breathing, fainting, severe confusion, or being hard to wake also requires emergency care.

A healthcare professional may ask when the odour began, where it comes from, and whether it changes with exercise, stress, food, or hormonal changes. They may also ask about sweating, skin symptoms, dental health, medicines, supplements, smoking, and alcohol.

An examination may identify excessive sweating, irritated skin, infection, wounds, or dental problems. Testing is not always needed.

Blood or urine tests may be considered if other symptoms suggest diabetes, thyroid problems, or kidney or liver disease. Skin or discharge samples may be tested for infection. A dentist can assess breath odour if gum or tooth disease is suspected.

Treatment depends on where the odour comes from and what is contributing to it.

Wash odour-prone areas regularly and after heavy sweating, then dry them carefully. Change damp clothing and socks promptly. Let shoes dry before wearing them again and choose breathable clothing when practical.

Antiperspirants reduce sweat reaching the skin, while deodorants mainly reduce or cover odour. Many products contain both. Follow the instructions and stop using the product if significant irritation develops.

Other helpful steps include:

• Washing and drying skin folds gently
• Recording possible food or drink triggers
• Cleaning dentures and maintaining regular dental care
• Avoiding perfume on irritated skin or intimate areas
• Not using vaginal douches, which can disturb normal bacteria

A clinician may prescribe treatment for excessive sweating or address a skin, dental, or medical cause. If a medicine may be contributing, discuss alternatives rather than stopping it suddenly.

Odour linked to heat, exercise, food, or temporary hormonal changes often settles when the trigger passes. Regular washing, dry clothing, and an effective antiperspirant help many people.

Odour caused by ongoing sweating or a skin condition may return without continued care. If the smell changed suddenly or is linked to another health problem, improvement depends on treating the cause.

Follow up if treatment is not helping, symptoms worsen, or the odour affects work, relationships, or emotional well-being.

Is body odour contagious?

Ordinary body odour is not contagious. However, some fungal or bacterial skin infections that contribute to odour can spread through close contact or shared towels, clothing, or footwear.

Why does deodorant sometimes not work?

Deodorant mainly targets smell and may not control heavy sweating. Antiperspirant reduces sweat, leaving less moisture for odour-producing bacteria. Irritation, incorrect use, or a skin problem can also affect results.

Can stress cause body odour?

Yes. Stress can activate sweat glands in the armpits and groin. This sweat may develop a stronger smell after interacting with skin bacteria.

Should I worry about a sudden change?

A brief change after certain foods, exercise, or a new product is often temporary. Arrange an appointment if it persists, has no clear trigger, or occurs with excessive sweating, pain, fever, discharge, weight change, or other symptoms.