Dandruff

What is it?

Dandruff (pityriasis capitis) affects approximately 50% of adults globally, making it one of the most prevalent dermatological conditions. It exists on a spectrum with seborrheic dermatitis — dandruff is the non-inflammatory end, while seborrheic dermatitis involves visible erythema and greasier, more adherent scale. The yeast Malassezia globosa colonizes sebum-rich areas and produces oleic acid, which disrupts the skin barrier and triggers rapid epidermal turnover. Dandruff is not caused by poor hygiene; in fact, washing too infrequently worsens it. Scalp psoriasis is a common differential diagnosis, distinguished by thick silvery plaques, sharp lesion borders, and nail involvement.

Common causes

When to see a doctor

• 1Scalp flaking with thick adherent plaques, sharp margins, and nail pitting — evaluate for psoriasis
• 2Scalp flaking in a child with patchy hair loss — possible tinea capitis (fungal infection)
• 3Dandruff unresponsive to 4–8 weeks of OTC antifungal shampoos
• 4Severe scalp pruritus with excoriations — may require prescription treatment
• 5Seborrheic dermatitis involving the face, eyebrows, nasolabial folds, or ears

What you can do

• ✓Wash hair more frequently, not less — regular shampooing removes scales and reduces Malassezia load
• ✓Leave antifungal shampoo on for 3–5 minutes before rinsing for maximum effect
• ✓Alternate between two different anti-dandruff shampoos to prevent resistance
• ✓Avoid hair products with heavy oils or greasy conditioners — they feed Malassezia
• ✓Manage stress — flares are common during periods of psychological stress

Conditions that cause this symptom

Medications that may help

Treatment depends on the underlying cause. Always consult your provider before starting any medication.

Frequently asked questions