The Bottom Line

Dandruff is one of the most common scalp conditions in the world — about 50% of adults deal with it at some point. It's caused by a yeast called Malassezia that naturally lives on the scalp. It's not contagious, not a sign of poor hygiene, and it does not cause permanent hair loss. The right shampoo almost always keeps it under control.

What Is Dandruff?

Dandruff is the mildest form of seborrheic dermatitis — a skin condition that causes your scalp to shed flakes of skin. You'll notice white or yellowish flakes on your hair and shoulders. Some people also feel an itchy or oily scalp. Unlike the more severe form of seborrheic dermatitis, dandruff does not cause redness or visible skin irritation.

Dandruff is not caused by washing your hair too little. In fact, washing too often or too aggressively can sometimes make it worse by drying out the scalp. It is also not contagious — you can't pass it to someone else.

Why Does Dandruff Happen?

Three things work together to cause dandruff:

  • Malassezia yeast — a naturally occurring fungus that lives on almost everyone's scalp. In some people, it grows too much and triggers flaking.
  • Excess skin cell shedding — your scalp renews itself faster than normal, producing more flakes.
  • Your body's reaction — Malassezia produces a fatty acid (oleic acid) that irritates the skin in genetically susceptible people, leading to itching and more shedding.

Dandruff tends to be worse in cool, dry weather. It often starts during the teen years, peaks in your 20s and 30s, and tends to improve after age 60. Men are slightly more likely to have it than women.

What Does Dandruff Look Like?

  • Fine white or yellowish flakes on your scalp, hair, and shoulders
  • Mild-to-moderate itching (some people have none at all)
  • Scalp that feels greasy or dry depending on your skin type
  • No redness or inflamed patches (if those appear, it may be seborrheic dermatitis)

Treatment Options

Antifungal and Medicated Shampoos (First Choice)

Most people get good results from over-the-counter dandruff shampoos used two to three times a week. Leave the shampoo on for 5 minutes before rinsing for better results. Key ingredients to look for:

  • Zinc pyrithione (Head & Shoulders, Selsun Blue) — works for 60–75% of people
  • Ketoconazole 2% (Nizoral) — highly effective, works for 75–85% of users
  • Selenium sulfide 2.5% — similar results to zinc pyrithione
  • Salicylic acid — helps lift and remove built-up scale
  • Coal tar — anti-inflammatory; can stain light hair with prolonged use

Prescription Options

If over-the-counter shampoos don't fully control your dandruff, a dermatologist may recommend a stronger prescription antifungal shampoo, a topical corticosteroid solution to ease scalp inflammation, or a topical antifungal cream or lotion applied between washes.

Ongoing Maintenance

Dandruff tends to come back if you stop treatment. Most people do best with a maintenance schedule — using a medicated shampoo once or twice a week even after flaking clears up.

When to See a Dermatologist

  • Dandruff shampoos used consistently for 4–6 weeks haven't helped
  • Your scalp is red, swollen, or has thick patches of scale
  • You notice unusual hair shedding along with the flaking
  • You're unsure whether you have dandruff, psoriasis, or a fungal infection
  • Itching is severe enough to disrupt sleep or daily activities

Frequently Asked Questions

Is dandruff caused by poor hygiene?

No. Dandruff is caused by a yeast overgrowth and your scalp's reaction to it — not by how often you wash your hair. Some people who wash their hair every day still get dandruff, while others who shampoo less frequently do not. However, going too long between washes can allow scale to build up and increase itching.

Can dandruff cause hair loss?

Dandruff itself does not cause permanent hair loss. Scratching the scalp forcefully or repeatedly can cause temporary hair breakage and shedding, but new hair grows back normally once the scalp irritation is controlled.

Why does dandruff come back after treatment?

Malassezia is a permanent resident of the scalp — it can't be permanently eliminated. Medicated shampoos keep it at manageable levels, but stopping treatment allows it to overgrow again. Most people need long-term, intermittent use of a dandruff shampoo to stay flake-free.

Is dandruff the same as scalp psoriasis?

No. Scalp psoriasis causes thicker, well-defined silvery-white scale, usually with distinct red borders and more intense itching. Dandruff produces finer, looser flakes without clear borders or significant redness. A dermatologist can distinguish between the two during an exam.

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  2. Gupta AK, Bluhm R. Seborrheic dermatitis. J Eur Acad Dermatol Venereol. 2004;18(1):13-26.
  3. Schwartz JR, et al. A comprehensive pathophysiology of dandruff and seborrheic dermatitis. Int J Dermatol. 2006;45(Suppl 1):1-9.
  4. Hay RJ. Malassezia, dandruff and seborrhoeic dermatitis: an overview. Br J Dermatol. 2011;165(Suppl 2):2-8.
  5. DeAngelis YM, et al. Microbial and physiological changes with efficacious dandruff treatment. J Invest Dermatol. 2005;125(5):1017-1024.

Trusted Resources

Always consult a board-certified dermatologist before starting or changing any treatment for scalp conditions.