Dandruff is a common skin problem that affects about half of the world’s population. It causes white, flaky skin to appear on the scalp, making hair – particularly dark hair – look dirty. Scalps with dandruff are often dry and itchy, making you want to repeatedly scratch your head and causing more white flakes to appear.
While dandruff is unpleasant and inconvenient, it isn’t a direct cause of balding. However, it’s associated with multiple conditions that can cause hair loss. And it’s often indicative of an issue with the amount or types of microorganisms living on your scalp.
What causes dandruff?
Dandruff occurs when there’s an imbalance in the scalp microbiome. It typically occurs when there’s a decrease in certain beneficial bacteria and an increase in harmful bacteria and fungi.
According to a study in Nature Reviews Microbiology, human skin – including the scalp – is home to millions of different microbes. While we usually associate bacteria, fungi, and viruses with sickness, millions of these tiny microorganisms live on our scalp. But unlike the microbes that cause illness, most of these microorganisms are beneficial, helping protect us from disease.
Yeast-like fungi cause dandruff
Dandruff usually occurs when an excessive amount of certain types of Malassezia, a yeast-like fungus, colonizes your scalp. According to an article in the Indian Journal of Dermatology, there are 14 different types of Malassezia. Most of these species don’t cause serious illness.
Usually, Malassezia globosa is believed to be the culprit behind dandruff. However, a study in the journal Infection, Epidemiology, and Medicine also linked Malassezia furfur, Malassezia restricta, Malassezia sympodialis, and Malassezia slooffiae to scalps affected by this issue.
Bacteria cause dandruff
An imbalance in scalp bacteria has also been associated with the skin issues that cause dandruff, like seborrheic dermatitis. Studies in Nature Scientific Reports and Experimental Dermatology say that dandruff has been linked to scalps with large amounts of Staphylococcus, Candida, Aspergillus, and Filobasidium bacteria. In most cases, it seems that dandruff is caused by too much Staphylococcus alongside a decrease in beneficial bacteria (like Cutibaterium or Propionibacterium).
Can dandruff cause hair loss?
Dandruff doesn’t directly cause hair loss – but it can be related to it. Dandruff is related to your scalp’s sebum production. Sebum is an oily substance that is secreted from the body’s sebaceous glands. Certain microbes, like Malassezia, live off the fats found in scalp sebum.
According to the book Applied Dermatotoxicology: Clinical Aspects, sebum production is mainly regulated by androgenic hormones. Androgens are also the hormonal component behind the most common type of hair loss: male pattern baldness (also known as androgenic alopecia). The book Androgenetic Alopecia From A to Z says that scalps affected by pattern hair loss have increased sebum production. This increases the likelihood that your scalp will be colonized by the harmful bacteria that cause dandruff.
Is dandruff a sign of male pattern baldness?
Dandruff isn’t a cause of pattern hair loss. This type of alopecia is caused by two main factors: genetics and an androgen called dihydrotestosterone (DHT). It typically starts with a receding hairline, then evolves into hair thinning across the top of the head, particularly at the temples and crown.
However, according to a study in the journal Microorganisms, the same bacteria and fungi that have been associated with dandruff have been found on the scalps of people with androgenic alopecia. And these same microbes have been associated with microbial overgrowth and inflammation that can affect the health of your hair follicles.
If you have androgenic alopecia, your hair follicles are gradually getting smaller over time due to a process called miniaturization. This gradual shrinkage occurs when DHT binds to hair follicles. It causes smaller, thinner hair strands to be produced until eventually, the hair follicles completely stop producing hair.
People with both dandruff and hair loss caused by androgenic alopecia may find that the miniaturization process occurs at an accelerated rate. This is because inflammation and microbial overgrowth have a negative impact on your hair follicles – which are already being affected by DHT.
How to get rid of dandruff and hair fall
For most people, getting rid of dandruff isn’t actually too challenging. A number of products are sold – both over the counter and on prescription – to treat this common scalp condition. According to the book Practical Modern Hair Science, these products contain ingredients like:
- Pyrithione zinc
- Selenium sulfide
- Salicylic acid
- Coal tar
- Piroctone olamine
- Ciclopirox olamine
You can usually buy shampoos with ketoconazole, zinc pyrithione, or selenium sulfide at your local supermarket or pharmacy. These active ingredients are found in a variety of well-known shampoos, like Head and Shoulders and Nizoral. After a few weeks of using one of these products, your dandruff should be gone.
But of course, getting rid of dandruff isn’t easy for everyone. Some people may need to take oral steroids, use topical steroids, or try a stronger version of one of these shampoos (which are only available with a doctor’s prescription).
Improving your scalp microbiome will also improve the health of your hair follicles. But be aware that these products aren’t able to combat hair loss. They can certainly help, but they aren’t a cure-all. Currently, the only FDA-approved treatments that can stop the progression of androgenic alopecia are minoxidil, finasteride, and low-level laser therapy.
Can a hair loss treatment stop dandruff?
Wouldn’t it be convenient if minoxidil, finasteride, or low-level laser therapy could stop dandruff? Unfortunately, while these hair loss treatments can improve hair thickness and hair growth, they aren’t able to improve your scalp microbiome – at least, not in the same way an antimicrobial agent can.
Minoxidil is a topical medication that increases blood flow to hair follicles. This allows more nutrients and oxygen to reach follicles. While this may help combat the effects of DHT and inflammation, it isn’t able to kill off the fungi or bacteria causing dandruff.
Finasteride is a DHT blocker that’s sold as an oral medication. Its anti-androgenic properties are able to reduce DHT and consequently may be able to improve inflammation and sebum oversecretion. But, like minoxidil, it doesn’t have the antimicrobial ability to kill off the fungi and bacteria behind dandruff.
Low-level laser therapy can be obtained through a variety of different portable devices, including laser caps, combs, and hairbands. This biostimulatory treatment is able to encourage healthy hair growth. And while it might seem like lasers would definitely be able to kill bad bacteria and fungi, there’s no evidence showing that low-level lasers can kill microbes – much less selectively kill the ones on your skin that cause overgrowth and disease.
But the good news is that you can use medicated shampoos alongside any of these hair loss treatments without any issue. In fact, a study in the journal Dermatologic Therapy says some of these active ingredients, like ketoconazole, have anti-androgenic properties and can help improve hair growth. If you combine a product like minoxidil or a low-level laser therapy device with a DHT-blocking shampoo, you may very well improve your overall hair regrowth results.
What if minoxidil is the cause of dandruff?
Minoxidil is a hair loss treatment that’s available as a liquid serum and a foam in concentrations of 2 and 5 percent. While the active ingredient (minoxidil) is the same regardless of concentration or formulation, other inactive ingredients can differ across products.
According to a study in the Dermatology and Therapy journal, some minoxidil products contain an ingredient called propylene glycol, which can cause allergic reactions. There’s more of this ingredient in higher concentration minoxidil products.
If you’re having a propylene glycol allergic reaction, you may find that your scalp looks dry, red, and irritated, and feels itchy. If this reaction continues, it can cause dandruff – usually because of allergic contact dermatitis.
This form of dermatitis and the resulting dandruff should go away pretty quickly if you stop using minoxidil. But fortunately, you don’t have to write off the whole hair loss treatment. You can just swap to a non-alcohol-based minoxidil solution that doesn’t contain propylene glycol.
Does dandruff stop hair growth?
Dandruff is a condition that causes itchy, dry, flaky skin. When you see the white flakes associated with dandruff, it usually indicates that your scalp is experiencing microbial overgrowth. These microbes are linked to inflammation – and there is a well-established relationship between scalp inflammation and hair loss, particularly androgenic alopecia.
Dandruff can’t directly cause hair loss, but if left untreated, it can certainly impact the health of your hair follicles negatively. And the inflammation associated with it can also increase the severity of your hair loss symptoms and accelerate the progression of pattern baldness.
Fortunately, many different products can treat dandruff. Shampoos containing ingredients like ketoconazole, zinc pyrithione, and selenium sulfide are available over the counter. And for those who need clinical-strength products, higher concentration products are also available with a prescription.
Just remember that an anti-dandruff shampoo or hair product isn’t enough to stop hair loss. To regrow hair, you’ll need to use minoxidil, finasteride, or laser hair therapy – all of which are FDA-approved to treat pattern hair loss.