If someone asked you to list the parts of the body mostly likely to generate an unpleasant smell, what would top your list?

You might first think of feet or underarms, but as it turns out, your scalp might be smellier than you realize. Learning to identify the most likely culprit can help you figure out the best way to reduce — or even eliminate — any unpleasant smells.

If you’ve wrinkled your nose upon getting a whiff of your own scalp, and it’s not just a one-time occurrence, you may need to consider the various possible causes of the smell.

Seborrheic dermatitis

Your sebaceous glands secrete oil, hence the name of this common skin disease.

Seborrheic dermatitis is thought to be caused by an overgrowth of a natural yeast that lives on our bodies. This causes dry, yellowish, scaly patches on the scalp — and it could be causing it to smell, too.

Excessive sweating

If you’re a gym regular who skips the post-workout shower, even after working up a sweat, your scalp may convince you to change your behavior.

When that build-up of sweat mixes with bacteria on your scalp, you may start to notice an unpleasant smell. Excessive sweating, also known as hyperhidrosis, can make it worse.

Under- or over-washing

When you delay a good scrub, you allow oils, or sebum, to build up on your scalp. This sebum can make your scalp and even your hair smell a little unpleasant.

Fungal infection

A smelly scalp could be the result of a fungus that lives on the skin. This fungus can cause inflammatory reactions like folliculitis, dandruff, and eczema.

Hormonal changes

Hormone changes affect your hair and scalp. For example, many women notice some hair thinning or even hair loss during menopause.

If your body’s producing excess amounts of androgen, that could result in an overproduction of oil from your skin’s glands — including those on your scalp.

Pollution

We tend to think of pollution (especially particulate matter like soot or smoke in the air) as being harmful to our lungs — and it is.

But exposure to environmental odors can cause all sorts of symptoms, ranging from headaches to nausea. These particles can also cling to your hair — and scalp — and make it smell bad.

Psoriasis

If you have scalp psoriasis, you may have fine scales covering your scalp, or you may have a series of thick, crusty plaques. You might be tempted to skip washing the affected area, but that might lead to the development of a smell as oil and skin cells build up.

Research shows that 7 to 26 percent of people with psoriasis go on to develop psoriatic arthritis. This requires treatment to stop or delay the development of possibly irreversible joint damage.

Your diet

Your diet — or changes to your diet — can result in body odor. For example, if you’re an enthusiastic carnivore, some research suggests that all that meat could affect the way that you (and possibly your scalp) smell to others.

Hair products

Some people buy hair products based solely on the scent of the product, while others focus more on the intended results.

However, even sweetly scented products can cause a build-up of oils on your scalp if they’re not washed out. That can lead to less-than-desirable odors.

Some people may be mystified by the cause of their smelly scalp. They might even wonder if there’s a mysterious smelly scalp syndrome that could be the culprit.

This hasn’t been documented in medical literature. However, there are other possible medical causes that might cause an unpleasant smell to emanate from the scalp, so it’s always worth talking to a doctor about those potential causes.

If you prefer to address your issue with a home remedy before visiting a doctor, consider these options:

Shampoo for a smelly scalp

If dandruff or seborrheic dermatitis are contributing to the smell emanating from your scalp, it might be worth washing your hair and scalp with a shampoo specifically formulated for this purpose.

The American Academy of Dermatology (AAD) suggests using a product with one of the following ingredients:

If your first choice doesn’t seem to work, try a shampoo with a different active ingredient next.

Essential oils

You might also consider a few essential oils as a possible remedy. Some people find that tea tree oil, which is antimicrobial, is effective at treating conditions that cause a smelly scalp, like seborrheic dermatitis.

Another possibility: lemongrass oil. A small study of 30 participants found that a tonic containing lemongrass oil was effective at reducing dandruff.

Apple cider vinegar

Apple cider vinegar has lots of fans for its various potential health benefits, which range from helping people manage their blood sugar levels to helping people lose weight.

But another key benefit of ACV is its antimicrobial properties. You may see some success in treating your scalp with apple cider vinegar.

If you have eczema, avoid using ACV. Additionally, some research suggests that certain people might experience irritation from using apple cider vinegar on their skin.

Try diluting it before applying it to your skin. Or, rub some onto the skin inside your elbow and wait for 24 to 48 hours to see if there’s a reaction before using it on your scalp.

Aloe vera

If you have seborrheic dermatitis, consider using aloe vera as a home remedy. Research shows that it can be an effective treatment for managing this chronic condition for some people.

Aloe vera has been used for a variety of dermatologic and other conditions for thousands of years, as it’s known for its antiseptic and anti-inflammatory properties.

Lemon juice

Could lemon juice be an antidote to your smelly scalp? Lemon juice has been shown to have antimicrobial qualities, which suggests that it could reduce some smell-generating bacteria lurking on your scalp.

Lemon juice is sometimes lauded for various positive effects it can have on your skin, but like many fruit acids, it can also be irritating and can make your skin more sensitive to sunlight. Use it with caution.

If home remedies aren’t effective, you should see a doctor. Depending on the cause, they may be able to recommend a medical treatment. For example, you might think you have dandruff, when instead it’s seborrheic dermatitis.

A doctor might suggest an oral antifungal medication, a medicated shampoo, or an antifungal cream on your scalp to attack the root cause of the condition.

If the cause is a fungus like Malassezia, the doctor might suggest a particular type of anti-dandruff shampoo containing pyrithione zinc, which research suggests should alleviate the problem.

There are a number of effective treatments for scalp psoriasis, including oral and topical medications. But many of them require a prescription.

If none of the strategies or treatments you’ve tried have reduced or eliminated the smell, make an appointment to see a doctor.

They’ll further evaluate more serious underlying conditions that may be present, and may recommend additional treatment.

If you’ve noticed a change in the odor of your scalp or hair, and there’s no obvious cause like a change in hair products, it might be worth consulting a doctor.

It could just be a matter of needing to wash your hair more often. But a chronically smelly scalp could indicate that some other condition is present that might warrant medical treatment.