If you’ve ever thought twice about wearing a dark shirt or jacket in case it ends up covered in a light dusting of flakes, you will know the annoyance that dandruff can cause. Lots of us will have to deal with this at some stage in our lives – and while it’s not dangerous, it can make you very self-conscious. But where does it come from, and what can you do about it?
What is dandruff?
Dandruff is a harmless – if irritating – condition that usually affects the skin of the scalp, causing it to be itchy and flaky. The flakes of skin can appear either white, yellow, or grey and tend to be more visible in darker hair, or if they fall down onto your clothes.
It’s a very common condition that normally starts to crop up after puberty, but there’s a similar condition called cradle cap that affects babies.
Dandruff can arise from a number of different underlying conditions, but it’s important to note that you cannot catch it from other people.
What causes dandruff?
Seborrheic dermatitis
According to the American Academy of Dermatology, dandruff itself may be considered a mild form of a condition called seborrheic dermatitis (SD), thought to affect around 3 percent of people, although estimates do vary.
In people with SD, the itchy, flaky patches can extend beyond the scalp to other areas of skin, such as behind the ears and around the nose. The condition also causes inflammation, and in more severe cases yellowish scales of dead skin can appear extensively on the scalp and attach to the hair shaft.
The condition is particularly common in infants, adolescents, and older adults, and in males. People who are HIV positive are at increased risk compared with the general population.
It’s thought that a major contributor to SD is an overgrowth of yeast in the genus Malassezia, particularly the species M. globosa and M. restricta. They are what’s termed a commensal fungus, meaning they live naturally on our skin, and it’s not completely clear why they cause issues for some people.
The National Eczema Association explains one theory, that excess sebum production may provide a hospitable environment for Malassezia, causing it to over-colonize the scalp in some individuals. There’s some research to suggest that free fatty acids left behind by the fungus may damage the skin barrier of the scalp, causing irritation that can lead to dandruff.
In 2019, some researchers put forward a perspective on the role of Malassezia in SD, suggesting that other potential causal factors should also be considered. They cited some evidence from animal studies that there could be a genetic component as well as a role for the skin microbiome, and argued that more research is needed to fully understand the causes.
A 2024 preprint, which is yet to be validated by peer review, explored the idea that the microbiome could be playing a role in dandruff. The authors found that propionic acid, produced by the skin bacterium Cutibacterium acnes can limit the growth of Malassezia and help prevent dandruff, suggesting that altering the microbial balance in favor of this species could be a possible route to treatment. However, only 57 participants were involved in their clinical study.
Other conditions
SD is not the only possible cause for a flaky, itchy scalp and finding snow on your shoulders in the middle of summer.
Another fungal infection, tinea capitis or scalp ringworm, causes a rash that can include some skin flaking, and even lead to hair loss. Psoriasis can also occur on the scalp, causing plaques of scaly skin and dandruff-like flaking. It’s also possible to experience flaking after an allergic reaction to hair products, known as contact dermatitis.
What are the latest treatments for dandruff?
The specific treatment you need may depend on the underlying cause of your dandruff. Here, we’re going to focus on regular dandruff and SD – but if you are concerned that treatments aren’t working or think your dandruff may be caused by another problem, it’s best to seek advice from a doctor.
Shampoo
For mild dandruff, it’s usually possible to get it under control using an antidandruff shampoo. Medicated shampoos typically contain an antifungal ingredient that targets dandruff-causing fungi, and you may find you need to try a few before you hit on one that works.
One common ingredient is pyrithione zinc, which has broad antifungal as well as antibacterial properties. One of its advantages is that it can remain on the skin even when the product carrying it has been rinsed off, continuing to work over a longer period of time.
A recent study looked at various shampoo formulations for SD with a focus on pyrithione zinc. It found that while levels of the ingredient delivered to the surface of the skin were sufficient to inhibit the growth of Malassezia, the effects of different formulations at the level of the hair follicle were more variable, suggesting that some may not have as long-lasting an effect. The authors made some recommendations for how future formulas may combat this to maximize their effectiveness.
Alternative antifungals include ketoconazole, miconazole, and selenium sulfide. Availability of these products can vary in different locations, so your best resource for finding out what might be accessible to you is your local pharmacy.
Some other antidandruff shampoos that can be effective contain coal tar, which is thought to work through its antimicrobial effects as well as by helping the dead skin cells to loosen and shed more easily. Coal tar can cause temporary discoloration of lighter hair, and may also make the skin of the scalp more sensitive to sunlight, so you should wear sunscreen and/or a hat while using these products.
You may find you need to alternate between different products if one stops working after a time. Once the dandruff is under control, it’s often possible to return to a regular shampoo and only use a medicated one occasionally for maintenance.
Treating more severe cases
For more severe SD, a doctor may prescribe a lotion or scalp treatment containing salicylic acid. This acts as an exfoliant, helping slough off the top layer of skin cells to limit the formation of plaques and scales.
You may also be able to get creams or shampoos containing higher concentrations of antifungal ingredients via a prescription from your doctor. In the most severe cases, such as in people who are immunocompromised and who may have widespread SD, an antifungal medication taken as a pill may be required.
Where there is more severe inflammation of the scalp, it may be necessary to use a topical corticosteroid for a short period of time, but again this would only be prescribed by a doctor.
Alternative remedies
There are a number of alternative and home remedies that people turn to for the relief of dandruff, with varying degrees of scientific backing.
One that pops up a lot is tea tree oil, and there was a study back in 2002 that concluded a shampoo containing 5 percent tea tree was effective at improving dandruff based on results from 126 people. Tea tree oil is a generally safe ingredient when used correctly diluted or in a formula like a shampoo, and it’s been used medicinally in its native Australia for centuries. It has antimicrobial properties, which may explain why it appears to work for some people with dandruff. A 2023 study examined a synthetic compound based on an extract from the tea tree plant, finding in in vitro studies – so not in live animals or humans yet – that it may have antibacterial and antifungal properties that could mean it would be of use in SD remedies.
Similarly, lemongrass oil is thought to have some potential antifungal effects. A recent review discussed this in addition to other purported health benefits of the extract, citing some evidence that it may disrupt fungal cell membranes and could be beneficial if included in antidandruff hair tonic formulations, but it’s difficult to draw firm conclusions at this stage without larger-scale research.
People may also turn to dietary supplements such as omega-3s, seeking to improve skin health generally. In general, supplements may be a good option if, for example, you need to follow a restricted diet and are at risk of deficiencies, but they can’t replace the health benefits of a balanced diet and regular exercise.
Dandruff is certainly irritating, and can have a marked impact on quality of life, causing embarrassment and discomfort. Luckily, most people will be able to find a treatment that works for them – you might just have to be prepared for a little trial and error first.
All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.
The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.
Source Link: Why Is My Scalp Flaky? Exploring The Causes Of Dandruff And How It’s Treated