Key takeaways
- Researchers describe dandruff and seborrheic dermatitis as points on one spectrum.
- Dandruff stays on the scalp and involves itching and flaking without visible inflammation; seborrheic dermatitis is more inflammatory and can affect other areas.
- Flakes can look dry or oily, so appearance alone is a poor guide to the cause.
What it is
Dandruff is itchy, flaking scalp skin without visible redness. Seborrheic dermatitis is the more inflammatory end of the same spectrum and can appear on the scalp and other oil-rich areas such as the face. Flakes are usually white to yellowish.
What the evidence says
A comprehensive review estimates that the two conditions combined affect about half of the adult population. Contributing factors discussed include sebaceous (oil) gland activity, colonization by Malassezia yeast, and individual susceptibility, including skin barrier function, immune response, genetics, and stress. Antifungal shampoos are among the standard treatments described, and the review lists other conditions that can look similar, including psoriasis, atopic dermatitis, and tinea capitis.
What the evidence does not establish
The review does not separate "dry scalp" from dandruff as a distinct category, and it does not rank consumer shampoos. Because other scalp conditions can mimic dandruff, a product that does not help is a reason to seek diagnosis rather than switch products repeatedly.
Who may want to pay attention
Anyone with persistent flaking, redness, or itching, or with patchy hair loss, should consider an evaluation by a dermatologist.
Sources
- Borda LJ, Wikramanayake TC. Seborrheic dermatitis and dandruff: a comprehensive review. J Clin Investig Dermatol. 2015;3(2). doi:10.13188/2373-1044.1000019 Source
Last reviewed October 2026. Educational information only, not medical advice. Findings from one study or review do not apply identically to every person or product.