What fungus causes dandruff?

Malassezia is a yeast that normally lives on many people’s skin. In some scalps, interaction between the yeast, natural oils, and the skin barrier promotes irritation and faster shedding of surface skin cells. That produces visible flakes and may cause itch. The presence of yeast alone does not mean the scalp has a contagious infection.

Seborrheic dermatitis can cause a more inflamed version of this process, with redness and greasy scale that may extend beyond the scalp. A flaky scalp may also reflect dryness, psoriasis, contact irritation, or another problem, so appearance and symptoms matter.

Regular washing with a suitable anti-dandruff or medicated shampoo can reduce scale and limit the conditions that support excess yeast activity. The active ingredient and contact time matter, so use the product as directed and avoid getting it in the eyes.

If shampoo alone does not control symptoms, a clinician may consider topical antifungal treatment or check for a different diagnosis. Avoid scraping scales, as this can break the skin and intensify inflammation. Keep a note of products that trigger burning or worsening redness.

Arrange medical review if the scalp is very sore, oozing, swollen, or developing thick plaques, or if symptoms spread to the face or ears. Seek assessment for hair loss, broken hairs, or symptoms that persist despite careful use of an appropriate shampoo.

Ask whether your pattern fits dandruff or seborrheic dermatitis, which active ingredient suits your scalp, and how long to try it before changing treatment.