What causes dandruff?

Dandruff causes visible white or yellowish flakes that may fall onto clothing, with itch or scalp tightness in some people. The scalp’s oil and its normal yeast population can contribute to irritation and faster shedding without making the condition contagious. Cooler, drier weather, stress, and infrequent washing may make flakes more noticeable, while heavily fragranced or harsh products can irritate the scalp.

Redness, greasy scale around the scalp, eyebrows, ears, or sides of the nose may fit seborrheic dermatitis rather than simple dandruff. Thick plaques, sores, hair breakage, or marked inflammation call for an examination because psoriasis, eczema, allergy, or infection may need different care.

Wash regularly with a gentle routine and follow the directions for a medicated shampoo if one is recommended. Give the product enough contact with the scalp before rinsing, and avoid scratching, picking, heavy oils, and irritating hair products. If flakes persist, a clinician may suggest medicated shampoo treatment or a topical antifungal treatment based on the appearance and distribution.

Arrange a dermatology assessment when flaking does not settle with suitable scalp care, keeps returning, or extends beyond the scalp. Seek prompt attention for pain, bleeding, pus, thick plaques, sudden hair loss, or broken hairs. A diagnosis matters because an antifungal, anti-inflammatory, or other treatment may be needed depending on the cause.

Does this look like dandruff or seborrheic dermatitis, and which shampoo or topical treatment fits my scalp? Could any product I use be causing irritation?