Bromhidrosis is the medical term for excessive or abnormal body odor caused by bacteria breaking down sweat gland secretions and skin debris. Everyone produces some body odor, but bromhidrosis refers to cases where the smell is persistently strong enough to cause distress or social difficulty, going beyond what normal hygiene can easily control.
How Bromhidrosis Differs From Normal Body Odor
Sweat itself is essentially odorless. The smell people associate with sweating actually comes from bacteria on the skin surface decomposing the components of sweat into volatile acids. In most people, this process produces a mild odor that regular washing and deodorant can manage. Bromhidrosis occurs when this bacterial decomposition is unusually intense, producing a noticeably stronger or more persistent smell.
The condition is formally considered rare, though it is almost certainly underreported. Many people manage the problem on their own without ever seeing a doctor. Cultural context also plays a role in how often it gets diagnosed. In parts of East Asia, for instance, even mild body odor can carry significant social stigma, leading more people to seek medical treatment. In other regions, the threshold for considering body odor a medical problem is higher.
Apocrine vs. Eccrine: Two Types With Different Causes
Your body has two main types of sweat glands, and bromhidrosis can involve either one.
Apocrine bromhidrosis is the more common form in adults. Apocrine glands are concentrated in the armpits, groin, and around the nipples. They produce a thick, lipid-rich secretion that is sterile and odorless when it first reaches the skin. The problem starts when bacteria, particularly species of Corynebacterium, break that secretion down into pungent volatile acids. Research has consistently linked the abundance of Corynebacterium on the skin to the severity of bromhidrosis. Because apocrine glands don’t become active until puberty, this type of bromhidrosis appears exclusively in adolescents and adults, and it rarely affects elderly people. Men are more commonly affected, likely because they tend to have greater apocrine gland activity.
Eccrine bromhidrosis is less common overall but is actually the more frequent type in children. Eccrine glands are distributed across nearly the entire body and produce the watery sweat responsible for cooling you down. That sweat is nearly 100% water and normally doesn’t smell. Eccrine bromhidrosis happens when bacteria break down keratin, a structural protein in skin, that has been softened and loosened by prolonged moisture. This type can also be triggered by certain foods and substances, including garlic, onion, curry, alcohol, and some medications like penicillin, which alter the composition of sweat as the body processes them.
The Genetics Behind It
There is a genetic dimension to bromhidrosis that researchers have pinpointed to a single gene variant. Studies show a strong correlation between bromhidrosis and the type of earwax a person produces. People with wet, sticky earwax (as opposed to dry, flaky earwax) carry a variant of the ABCC11 gene that also increases apocrine gland secretion. This connection is well documented enough that earwax type can serve as a rough predictor of susceptibility to body odor problems.
Who Gets It and When
Apocrine bromhidrosis tracks closely with the timeline of puberty. It typically appears during adolescence, when apocrine glands first activate, and is most common during the years of peak gland activity. It becomes increasingly rare in older adults as those glands wind down. Eccrine bromhidrosis, by contrast, has no age restriction and can appear at any point in life. Overall, the condition is more common in men, though women can certainly be affected.
How It’s Diagnosed
There is no blood test or imaging study for bromhidrosis. Diagnosis is clinical, meaning a dermatologist evaluates it based on a physical examination and the patient’s reported symptoms. The key distinction a doctor is making is whether the odor represents something beyond normal body smell, whether it’s coming from the armpits (suggesting apocrine involvement) or from broader skin surfaces (suggesting eccrine involvement), and whether an underlying cause like diet, medication, or a metabolic condition could be contributing.
Managing the Odor
First-line treatment focuses on hygiene and topical products. This means showering promptly after sweating, laundering clothes after each wear rather than re-wearing them, and using antiperspirants rather than just deodorants. The distinction matters: deodorants mask odor, while antiperspirants contain aluminum-based salts that form temporary plugs in sweat ducts, physically reducing the amount of secretion that reaches the skin surface. Those aluminum compounds also have antibacterial properties, which directly targets the bacterial decomposition driving the smell.
Shaving underarm hair can also help, since hair traps moisture and gives bacteria more surface area to colonize. For some people, washing with an antiseptic soap for several days, sometimes combined with a topical antibacterial cream, is enough to reset the bacterial balance on the skin and bring the odor under control.
When hygiene measures aren’t sufficient, botulinum toxin injections into the affected area offer consistent improvement by temporarily blocking the nerve signals that trigger sweat production. The downside is that the effect wears off, typically after several months, requiring repeat treatments. Microwave-based therapies that permanently destroy sweat glands have shown promising early results, though the evidence base is still relatively small. For severe cases, surgical removal of sweat glands in the armpit is an option, but it’s generally reserved as a last resort.
Foods and Medications That Make It Worse
Because eccrine sweat carries trace amounts of whatever the body is metabolizing, certain dietary choices can temporarily worsen body odor even in people who don’t have chronic bromhidrosis. Garlic, onions, curry, and alcohol are the most commonly cited culprits. Their breakdown products are excreted partly through sweat, giving it a distinct and sometimes strong smell. Some medications, including penicillin-type antibiotics, can do the same thing. In these cases, the odor resolves once the food or medication clears the system.