One of the reasons one can be affected by odor from the scalp is the excess oil and sebum buildup on the scalp that can serve as a reservoir for bacteria and yeast to overgrow. After washing your hair with shampoo, there are significant variations amongst people with the process of hair regreasing. Read more...
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What Causes a Smelly Scalp?
One of the reasons one can be affected by odor from the scalp is the excess oil and sebum buildup on the scalp that can serve as a reservoir for bacteria and yeast to overgrow. After washing your hair with shampoo, there are significant variations amongst people with the process of hair regreasing.
What is hair regreasing?
Hair regreasing is how our scalp’s sebum and oil production migrate down the hair follicle post shampooing. Shampoo contains several ingredients- some of which are designed to break down excess oil and sebum to ‘degrease’ the hair and scalp. Once someone shampoos, the skin cells on the scalp start to produce more sebum and this migrates down the hair follicle to ‘regrease’ the hair. Within 48 hours, a study of men (think shorter hair based on studies) will ‘regrease’ the entire hair follicle. Those with longer hair will obviously take longer and may not feel the need to wash their hair as frequently. If one does not shampoo routinely, this oil and sebum can start to build up not just on the hair but the scalp itself. Once this buildup occurs then the bacteria and yeast that can overgrow may produce an odor. The frequency of the need to wash the hair is widely variable and person-specific. We all tend to have a personal sense of if we don’t wash our hair by a certain point then it will start to look excessively oily or greasy.
Are there other reasons for odor buildup in the scalp?
Another condition resulting in the potential for odor buildup is craniofacial hyperhidrosis. This is a condition where one sweats excessively from the face and scalp. It can be primary or secondary.
Primary craniofacial hyperhidrosis is thought to occur in people who simply have a higher concentration of sweat glands. Secondary craniofacial hyperhidrosis is the result of other causes: menopause, stress, fevers, increased temperature, illnesses, etc. The bottom line is that either there are more sweat glands OR the sweat glands present are more active because of the triggers listed above.
How can craniofacial hyperhidrosis be treated?
There are lots of ways to address this. Topical agents that include aluminum chloride can be applied to reduce excess sweating. There are over-the-counter preps such as certain dri that come as a wipe-and-toss pad or prescription liquids.
These don’t have to be used daily. Many people find that applying a couple of times a week can help. If this doesn’t work, there is a medication by mouth called glycopyrrolate or Robinol. I prescribe this routinely but with caution. It reduces sweat from head to toe and can be absolutely life-changing. We can titrate the dose for the best results. The thing to remember is that other secretions also dry out: dry eyes and dry mouth can occur. I ask that patients drink lots of fluids and use rewetting drops for the eyes. Botox injections can be very effective as well.
Are there at-home remedies for smelly scalp?
For some, over time there can be a ‘build up’ of residues from hair products, shampoos, and conditioners as well as an accumulation of natural oils and dead skin cells. Exfoliating or treating this build-up does help return hair’s natural luster and make the scalp less ‘flaky’ or dry and hopefully less itchy. For others, inflammation can lead to significant scaling and flakiness of the scalp. Common examples of this are psoriasis and seborrheic dermatitis. For these conditions, exfoliating the scalp or trying to actively remove or dislodge this scale can result in significant discomfort, raw or tender sensation, and even bleeding. This scaling and flakiness can be treated, however, the approach is different. Understanding and accurately diagnosing the causes of different scalp conditions is important prior to deciding to use a scalp exfoliator. Regardless of the cause of buildup, flakiness or scaling to the scalp, this really should be addressed. Any kind of build-up or scaling can result in a few problems. The buildup of dead skin cells and oils from not washing routinely or from product buildup that is not addressed can make our scalp feel itchy. This itching can cause flakes and dead skin cells to fall on our clothing which can be a bit embarrassing when wearing darker-colored clothing. Excess itchiness can result in hair breakage as well. If the dry flaky scalp is the result of inflammation, then the underlying cause of the inflammation should be treated or addressed. If the inflammation becomes chronic, then it can interfere with hair growth and become a source of discomfort as well. If your scalp issues are related to bacteria, it may be somewhat helpful to consider ACV diluted 1 part ACV to 3 parts water to help prevent. However, if your issues are dandruff related you may need to do 1 part ACV to 1 part water as this should be able to retain more effectiveness to the yeast that triggers dandruff.
Are there ways to prevent a smelly scalp?
Choose a shampoo that specifically addresses yeast that can help reduce yeast buildup such as ketoconazole.
Consider products that contain the following ingredients to address buildup.
Most products marketed as scalp exfoliants use ingredients intended to chemically exfoliate the scalp similar to acne products or hydrating ingredients intended to address itching and flaking of the scalp.
Common ingredients to consider... Charcoal
Charcoal has become a popular ingredient for products to include when targeting excess oil or impurities. Although I could not find a single medical study to show the effectiveness of charcoal in treating scalps directly, I can find potential benefits to using products that contain it. What is charcoal? Activated charcoal used in products and in medicine is made by heating substances rich in carbon such as wood, sawdust, coconut shells, etc. This is an interesting process because it allows the carbon to become more adsorbent. Adsorbent means that it can bind more molecules. In medicine, activated charcoal has been used to treat overdoses and poisonings as it can adsorb these toxins quickly. It has been used in wound healing in addition to a number of other uses. Charcoal applied to the skin is overall harmless and is not likely to irritate the skin. The theory behind adding it to products is that it may possibly absorb extra oil from the skin. If you have found a benefit in treating your scalp with charcoal-containing topicals then it is perfectly ok to continue. It would likely be best for people that have an oily scalp. It is a milder alternative to help reduce the oiliness without excessively drying the skin or hair.
Coconut oil
Coconut oil is gaining a lot of attention in skin care products. It is a proven emollient that can effectively hydrate the skin. It also has antimicrobial and anti-inflammatory properties. These can be beneficial for dry flaky scalps to help hydrate and improve scaling or flaking to the scalp.
Apple cider vinegar
I don’t think a day goes by where a patient doesn’t tell me that they used apple cider vinegar to treat something! ACV has anti-yeast properties and has been used to even treat diaper rash. Seborrheic dermatitis is thought to be related to yeast that is overgrown on our skin. It can often be added to scalp exfoliators to help address the underlying yeast that triggers inflammation resulting in scaling.
Tea tree oil
Tea tree oil has become one of the most common ingredients to find in skin care products. It is known for its antimicrobial and antiseptic properties in its activity against bacteria, viruses, fungi, mites, etc. When added to scalp exfoliators it is likely addressing some of the underlying triggers for scalp inflammation that result in scaling and itching. The only caution is that it does have about a 1-2% chance of causing contact dermatitis in those that use it. If using a product that has tea tree oil and your itching and flaking are getting worse, it’s essential to take a look at your products and make sure they are not making it worse!
Salicylic acid
Salicylic acid breaks apart superficial skin cells to help remove dead skin cells from the surface. It is used in acne medications but can also be found in higher concentrations in wart treatments. It can be effective without being too irritating. In scalp products, it can help remove excess dry skin and scale.
Are there medical treatments for smelly scalp?
Ultimately, once the inflammation builds, we can treat it with topical steroids or intralesional steroid injections to reduce inflammation quickly and help restore the scalp. Occasionally oral or topical antibiotics may be indicated to reduce bacterial buildup as well.
When is it time to see a doctor about smelly scalp?
Persistent flaking, dryness, and redness are important reasons to consider seeing your doctor.
Breakouts, scabs, pimples, and/or bumps in the scalp can indicate bacterial overgrowth and require antibiotics.
Another symptom that many people do not recognize is the sensitivity of the scalp and perhaps even getting a sense that you are very aware of which direction your hair is moving in. Some people will say that it almost feels like their hair was in a ponytail and they feel it sore and very aware of their scalp.
Excess sweating that is difficult to control can also be an important reason to see your doctor as well.
