Dandruff is characterized by a flaky, itchy scalp and affects about 50% of the adult population. It’s most likely caused by Malassezia yeast colonization, high sebum production, and other immune and skin factors. Special hair and scalp products are the most common treatment.
- Skin flakes on the scalp, hair, eyebrows, beard, or shoulders.
- Itchy scalp
Dandruff can occur completely on its own, but sometimes is a symptom of other illnesses like HIV/AIDS, neurological disorders (e.g., Parkinson’s disease, tardive dyskinesia, epilepsy), hepatitis C, chronic alcoholic pancreatitis, and some congenital disorders like Down syndrome.
Dandruff is mainly treated with hair and scalp products, such as shampoos. These products typically contain antifungals (e.g., ketoconazole, pyrithione zinc, selenium sulfide), corticosteroids (e.g., hydrocortisone or fluocinolone), or compounds that slow skin turnover or flake accumulation (e.g., coal tar, salicylic acid). Many of these products are available over-the-counter, but some require prescriptions.
The connection between diet and dandruff isn’t well described. However, intake of dietary fats, glucose, and acetate can all increase sebaceous gland activity, so a diet lower in these nutrients might help dandruff. Similarly, caloric restriction can reduce sebum production, and thus may ameliorate dandruff.
The causes of dandruff are not completely understood, although high levels of sebum secretion, the presence of the Malassezia genus of yeast (which feed on lipids present in sebum), and individual factors (e.g., skin barrier strength, immune response, genetics, neurological factors, and stress levels) are all thought to contribute to a person’s risk of having it. It’s worth noting that Malassezia is also found on many healthy people, which suggests host (individual) factors contribute strongly to the development of the condition.