Is dandruff the same as seborrheic dermatitis?
Dandruff and seborrheic dermatitis sit on one spectrum but are not identical: dandruff is usually scalp flaking without obvious inflammation, while seborrheic dermatitis can add redness, itching and greasy scale and spread to the eyebrows, sides of the nose and behind the ears. If ketoconazole 2% shampoo is used, the UK product information gives clear numbers: twice a week for 2–4 weeks, left on for 3–5 minutes before rinsing, and once every 1–2 weeks to prevent relapse.
Key numbers
- Twice weekly × 2–4 weeks — Ketoconazole 2% treatment
- 3–5 minutes — Contact time
- Once every 1–2 weeks — Maintenance/prevention
- 58% and 26% — Ciclopirox in AAD-cited trials
When is it not just dandruff?
- Clear redness or inflammation spreading to the eyebrows, around the nose and behind the ears points to seborrheic dermatitis wider than simple dandruff.
- Very thick scale, well-defined patches with hair loss, discharge or pain need a different diagnosis such as psoriasis, scalp ringworm or contact dermatitis.
- Relapse is common, so intermittent preventive treatment may be more realistic than waiting for the next flare.
Key takeaways
- Ketoconazole 2% is not a shampoo to rinse off immediately: contact time is 3–5 minutes.
- The usual treatment in the label is twice weekly for 2–4 weeks, then maintenance every 1–2 weeks if needed.
- Inflammation outside the scalp makes the diagnosis broader than simple dandruff.
Dandruff and Seborrheic Dermatitis: Causes and Treatment