Dandruff is a common scalp condition that causes the skin on the scalp to flake. These flakes are typically white or yellowish and can be visible in your hair and on your shoulders. It often comes with an itchy scalp.

What causes dandruff?

Dandruff is largely linked to a mild form of seborrheic dermatitis, an inflammatory skin condition. The primary cause for most dandruff cases is an overgrowth of a naturally occurring yeast-like fungus called Malassezia globosa. This fungus lives on almost everyone's scalp and feeds on the natural oils (sebum) produced by the scalp.

When Malassezia globosa multiplies too much, it breaks down the sebum into byproducts like oleic acid. About half the population is sensitive to oleic acid, and in these individuals, the scalp reacts by:

Increasing skin cell turnover: The body tries to shed the irritant faster, leading to an excessive accumulation of dead skin cells that become visible flakes.

Inflammation and irritation: This causes the itching, redness, and discomfort often associated with dandruff.

Several factors can trigger or worsen dandruff:

Oily scalp: Malassezia thrives in oily environments.

Infrequent shampooing: Allows oil and dead skin cells to build up.

Stress: Can weaken the immune system and worsen inflammation.

Hormonal changes.

Certain hair care products: Can irritate the scalp.

Underlying skin conditions: Like eczema or psoriasis.

Weakened immune system: More common in individuals with certain medical conditions.

Cold, dry weather: Can sometimes exacerbate flaking.

Symptoms of Dandruff:

White or yellowish flakes on the scalp, in hair, and on clothes.

Itchy scalp.

Redness or irritation of the scalp.

Greasy or dry scales on the scalp.

In severe cases, yellowish to reddish scaly raised bumps along the hairline.

It's important to distinguish dandruff from a simple dry scalp, which also causes flakes but typically smaller, whiter, and less oily flakes, and the scalp itself feels dry and tight rather than greasy or inflamed. Dry scalp is due to lack of moisture, while dandruff is often linked to excess oil and fungal overgrowth.