What Really Causes Dandruff? The Unexpected Facts.

Do you think twice before wearing black? Hesitate before sharing a hat, pillow, or yoga mat? Constantly struggle with ruffling your hair or scratching your scalp? We get it. Dandruff (colloquially called ‘flaking’) really can affect every part of your life - and for many of us, it can be an ongoing embarrassment, annoyance, and sometimes even painful affliction. 

Fortunately, you’re not alone. Far from it. In fact, nearly 75% of people experience symptoms of dandruff at some point in their lives, and roughly 20% get it chronically (all day, every day). Those impacted range from young children and adolescents to elderly people, and everyone in between. It is incredibly common, and yet for some reason, carries a stigma.

Malassezia is a single-celled organism - a type of yeast - that lives on everyone’s skin. The presence of this naturally-occurring fungus on your scalp is the most common culprit behind dandruff, and the most likely cause of flare-ups for people with seborrheic dermatitis. When it consumes the oil your scalp produces, it excretes waste products, including oleic acid – to which many individuals are mildly allergic. Your body tries to protect itself by shedding large pieces of skin - the characteristic white flakes of dandruff that you see.

The easiest way to stop this cycle is with a Zinc Pyrithione-based shampoo. Zinc Pyrithione effectively rids your scalp from fungal causes of dandruff in two ways: 

First, it reduces the number of lipid-promoting enzymes on your scalp. When you get rid of the excess oils, the Malassezia fungus won’t grow and multiply. 

And second, the shampoo increases the amount of zinc and copper in the cells of your scalp, which control the yeast and prevent fungal overgrowth.

Dandruff can also be caused simply by a dry scalp. Your scalp can be dry for a number of reasons - the weather, the kind of shampoo or styling products you use, types of moisturizing products, or due to the natural effects of aging. Usually, if dry scalp is the cause of your dandruff, you’ll notice smaller, whiter flakes - as opposed to the larger, yellow flakes associated with seborrheic dermatitis. 

When you have a dry, itchy scalp, consider whether you may be over or under-washing your hair. Our scalps produce oil at different rates - so while a daily wash might be right for one person, it could lead to dryness for someone else. If the frequency of washing doesn’t seem to be the problem, your shampoo or conditioner itself may be an issue. Choose a shampoo that treats flakes to cleanse and a conditioner that moisturizes to soothe your dry scalp condition.

Psoriasis is a common and chronic skin condition characterized by the build-up of excess cells on the skin’s surface. People with this medical condition suffer from areas of the body with flaky skin, dry skin, and inflamed (red) skin. It can be itchy and/or painful, and a variety of topical ointments (both prescription and over-the-counter) have been used to treat it. 

Some with scalp psoriasis will try apple cider vinegar or tea tree oil to alleviate their symptoms. Apple cider vinegar can help relieve the itchiness, and sometimes removes psoriatic scale, but it won’t actually effectively treat the underlying condition causing the symptoms. And although many people believe tea tree oil helps with psoriasis and other causes of flaky skin or scalps, there is little clinical evidence that it does.

When psoriasis is localized to the scalp, it can cause flaking and itching. This irritation can lead to dandruff, try using a medicated over-the-counter shampoo for dandruff with Zinc Pyrithione, coal tar or salicylic acid to help address the flaking, however you'll want to work with a dermatologist to specifically treat psoriasis and find the right medicated shampoos and lotions for you.