What causes dandruff in the hair?

The scalp naturally sheds skin and supports microorganisms, including a yeast called Malassezia. In some people, oil and sensitivity to this yeast promote irritation and faster shedding, producing white or yellowish flakes. Cold or dry conditions, stress, and infrequent washing may make symptoms more noticeable, but dandruff is not a sign that someone is dirty.

Redness, greasy scale, or flaking around the eyebrows, ears, or nose can suggest seborrheic dermatitis rather than simple dandruff. Thick plaques, marked inflammation, or hair loss can have other causes, including psoriasis or an infection. Examining the scalp matters when the pattern is unusual.

A medicated shampoo may contain an ingredient that reduces yeast, loosens scale, or calms inflammation. Follow its label or clinician’s instructions, work it into the scalp rather than only the hair, and leave it on for the recommended contact time. Once controlled, some people need less frequent maintenance use.

Avoid scratching, very hot water, and heavy styling products that cling to the scalp. If one shampoo irritates you or does not help after a consistent trial, a clinician can select another active ingredient or prescribe a topical antifungal treatment. Do not apply steroid or antifungal products to the scalp without advice when the diagnosis is uncertain.

Seek a dermatology review for painful sores, crusting, pus, bleeding, thick plaques, or patchy hair loss. Arrange care if flaking spreads to the face or ears, causes intense itch, or continues despite appropriate shampoo use. Urgent assessment is appropriate for facial swelling, fever, or rapidly worsening redness.

Does this look like dandruff or seborrheic dermatitis? Which shampoo ingredient should I use, and how long should it stay on? Could another scalp condition explain the scale or hair loss? When should I switch or return for review?