Body odour is natural, but sometimes it may signify a health issue. When body odour is persistent, unusual, and/or changes suddenly, it could indicate a possible health problem. Sweat itself is odourless, but when it interacts with bacteria on the skin, it creates the odour that we associate with body odour. Some of the factors that may alter the way the body smells are medications, hormones, and lifestyle choices. Dr Pooja Kanumuru, a dermatologist at Apollo Clinic, Indiranagar, addressed this for Health and Me.What does body odour indicate?There are medical conditions that can cause body odour to be unusual or excessive: bromhidrosis; bacterial and/or fungal skin infections; and systemic diseases such as diabetes, liver disease, and kidney disease. For example, a diabetic with poor management may have a fruity-smelling body odour, whereas an infected person may have a foul body odour due to bacterial activity.Body odour becomes an issue when there is no improvement despite proper hygiene. If body odour is associated with other symptoms such as fatigue, unexplained weight loss, fever, and/or abnormal skin changes, these should be addressed to determine the cause and seek appropriate assistance. Medically associated body odour does not decrease with normal methods such as bathing and/or the use of deodorants but tends to persist.Factors that affect body odourBody odour can also be affected by the following:Hormonal and metabolic changes during certain periods of life (for example, puberty, menstruation, pregnancy, and menopause) can change the amount of sweat produced, which can also alter the intensity of its smell.Thyroid disorders, especially hyperthyroidism, can sometimes result in increased sweating.Rare metabolic disorders, such as trimethylaminuria, can result in a strong, fishy-smelling body odour due to the inability to break down certain substances in the body.Clinical insights of body odourIt is interesting how certain unusual odours can offer important clinical insights. For example, if a person has a fruity odour, this could indicate difficulties with diabetes control. A fishy smell could be a sign of a metabolic disorder, while an ammonia-like smell may indicate problems with kidney function. Meanwhile, musty or foul odours may suggest an infection or liver dysfunction. While these odours cannot be used as stand-alone diagnoses, they can help guide further medical evaluation.Lifestyle changes to improve body odourDiet and lifestyle choices significantly affect body odour. For example, foods such as garlic, onions, spicy foods, red meat, and alcohol can exacerbate body odour, while poor hydration, high stress levels, smoking, and obesity can worsen it further. Additionally, wearing very tight or non-breathable clothing may cause perspiration and bacteria to become trapped, thereby worsening body odour.Keeping your body clean, applying the right type of antiperspirant, wearing breathable materials, and maintaining a healthy diet can all help in managing body odour. However, if body odour persists or worsens, you should consult a doctor. A prompt medical assessment can identify the cause and allow your physician to discuss possible treatments, including topical medications and procedures that reduce excessive sweating.