Flaky scalp - clinically known as pityriasis - is commonly associated with a number of scalp conditions. Whilst some of these conditions are more well-known than others, scalp flakiness can affect any of us, at any time, for any number of reasons. Having a working understanding of this symptom is always helpful. Knowing the conditions it’s most commonly associated with, their clinical features and available treatment options is useful, whether they’re curative or preventative.
What Causes a Flaky Scalp?
When it comes to the medical conditions associated with flakiness - dandruff and seborrheic dermatitis, which we will be focusing on in this post - many of them can be linked to the Malassezia fungus.
Though the jury is still out on this being a definitive causal link, the fungus’ strong involvement in the scalp condition continues to be supported by the fact that most (if not all) effective treatments to remedy flaking are designed to tackle this fungus. Malassezia is a genus of fungi that is present on the skin (and scalp) of every human - and many animals. This lipid feeding fungus exists in various forms/species - some of which have been found to have causal links with flaking in the scalp.
Why Does Our Scalp Flake?
In order to best understand how the different species of Malassezia cause flaky scalp, it’s best to begin by looking at how skin cells normally move up through the sub-layers of the skin and/or more specifically, the scalp.
The outermost layer of the skin (clinically known as stratum corneum) consists of roughly 30 layers of closely packed hardened keratinised cells. The top layer of these cells is constantly being shed, as it’s pushed out and replaced by the layers below (where new cells are constantly germinating). This shedding of dead skin cells typically goes unnoticed and certainly isn’t accompanied by any inflammation. In a healthy scalp, this cell turnover process takes about 30 days. Where flakiness is present, these layers are being pushed up at a far quicker rate, resulting in an increased turnover of dead skin cells that shows up as flakes or scales on the scalp.
Now that we’ve got that as a baseline, let’s delve into more specific species, how they cause flakiness, and how best to treat it and avoid it.
How Does the Malassezia Fungus Cause Flaky Scalp?
Being a lipid-loving fungus, Malassezia feeds on the natural waxy-like oil your skin and scalp produce (your sebum). What the Malassezia are particularly interested in are the free fatty acids that make up the sebum. As part of their ‘feeding’ process, the Malassezia will break down the sebum to take the particular fatty acids they require and leave the others. These remaining free fatty acids are then left to breach the skin barrier of the scalp - resulting in the irritation (itchy scalp, flaking, & dryness) that sufferers of dandruff typically complain about.
Dandruff & Seborrheic Dermatitis
The key fatty acid to note in this breakdown is oleic acid. Research has found dandruff and seborrheic dermatitis sufferers to be sensitive to oleic acid in a way that non-sufferers are not. In penetrating the layers of the skin, this acid causes it to increase its cell turnover rate - most likely in a bid to rid itself of the “unwanted substance”. This is what then translates to the scalp flaking white/grey residues that we see on the surface of the skin.
It is said that about half of the world’s population across all hair types share this sensitivity to oleic acid, making dandruff and seborrheic dermatitis a much more common condition than those who experience it realise. The truth is, all scalps have the Malassezia fungus. Yes, even the healthy scalps that don’t experience flaking. It is part of the natural microbiome of our scalp. So the question has never been how to eliminate them for good, but how to maintain a healthy balance that prevents excess Malassezia.
The name Seborrheic Dermatitis literally means excessive oiliness that results in irritation of the skin. Given what we know about the preferred diet of the Malassezia fungus, we can already see how excessively oily hair would be the perfect environment to encourage flare-ups of dandruff and seborrheic dermatitis. We can also use this information to plan the appropriate measures to prevent (or at least significantly reduce) flaking in the scalp.
How to Treat Flaky Scalp
- Cleanse regularly, and use a medicated shampoo if you’re already experiencing a flaking flare-up. Such shampoos are typically marketed as anti-dandruff cleansers and contain selenium sulphide, piroctone olamine, zinc pyrithione, or tar as the main active ingredients. These ingredients help to kill the Malassezia fungus, reduce the presence of free fatty acids, and prevent the resulting flaking and itching on the scalp. Research has shown that especially when combined with salicylic acid, shampoos containing piroctone olamine are particularly more effective than other commonly used actives (such as zinc pyrithione). How often you wash your hair is important to maintain a good scalp balance. Cleansing every 2-3 days is a good rule of thumb if you’re experiencing active flaking, and cleansing every 4-7 days is ideal for maintaining a healthy scalp regardless.
- Keep your microbiome in mind as part of your scalp care. Studies have shown associations between dandruff prone scalps and bacterial and fungal dysbiosis - which is a fancy way of saying an imbalance in the good vs. bad microbes on the scalp. Topical use of probiotics can help increase the population of good bacteria on your scalp, restoring the delicate balance to your scalp microbiome where it is difficult for the Malassezia fungus to thrive. If you’re unsure where to start, the Curlsmith Wash & Scrub is packed with microbiome-balancing ingredients, not to mention micro particles that gently exfoliate the scalp and wash off without leaving any residue or getting stuck in your hair. And it works even better when used as part of the three-step scalp clarifying system to help maintain the health of the scalp microbiome long term.
- Avoid applying oils directly to your scalp. This one should go without saying, but there’s no harm in saying it one more time. If the fungus that causes dandruff and seborrheic dermatitis depends on oils to thrive, any excessive oils on the scalp will only supercharge the inflammation, itching, flaking etc. So you should only focus on applying hair oil on your hair lengths. Choose an oil-free treatment for your scalp instead, like the Scalp Stimulating Booster or Full Lengths Density Elixir.
6 Signs You Need to See A Professional
Though the above are the most commonly experienced flaky scalp conditions, there are others that are a bit rarer and come with more severe markers of irritation. If the flakiness you’re experiencing resembles any of the following clinical features, be sure to contact your local dermatologist or trichologist at your earliest convenience.
- The scales resemble silvery-white patches on red inflamed skin.
- They are itchy and bleed when scratched.
- Flaking is accompanied by hair loss.
- Along with flaking, the scalp presents pimples, redness, and/or burning.
- Flakes/scales stick to the hair or cause the hair to stick flat against the scalp.
- Scales pile up to the point where the scalp feels lumpy.