These three can all cause a flaky or scaly scalp, but they differ in cause and treatment.
Dandruff (Seborrheic Dermatitis of the Scalp)
- What it is: A common, noncontagious condition linked to skin oils and a yeast on the skin’s surface.
- Signs: White/yellow flakes, mild redness, itch; greasier scales around scalp, eyebrows, sides of nose, ears.
- Treatment:
- OTC shampoos 2–3 times weekly: ketoconazole, selenium sulfide, zinc pyrithione, coal tar, or salicylic acid.
- Leave on 3–5 minutes before rinsing.
- For stubborn cases, clinicians may add a short course of prescription anti-inflammatory solutions or foams.
Scalp Psoriasis
- What it is: An immune condition causing skin cells to build up and form thick plaques.
- Signs: Thicker, silvery-white scales on well-defined red plaques; may extend beyond the hairline; can be itchy or sore. Often there are plaques on elbows, knees, or other areas, and pitted nails.
- Treatment:
- Prescription steroid solutions/foams, vitamin D analogs (calcipotriene), or combination products.
- Medicated tar/salicylic shampoos to soften scale; gentle scale removal after oils or moisturizers.
- Moderate-to-severe psoriasis may need phototherapy or oral/biologic medicines—see a dermatologist.
How to tell vs dandruff: Psoriasis plaques are thicker, more defined, and often extend past the hairline; dandruff is flakier, greasier, and more diffuse.
Scalp Ringworm (Tinea Capitis)
- What it is: A contagious fungal infection, most common in children.
- Signs: Round scaly patches with hair breakage (“black dots”), patchy hair loss; may have tender lymph nodes. Severe cases form a boggy, pus-filled lump (kerion).
- Treatment:
- Requires prescription oral antifungal medicine (e.g., terbinafine or griseofulvin) for weeks—shampoos alone won’t cure it.
- Antifungal shampoo (ketoconazole or selenium sulfide) 2–3 times weekly helps reduce spread.
- Check close contacts and pets if infections recur.
When to seek care
- Dandruff that doesn’t improve after 4–6 weeks of proper shampoo use.
- Thick plaques, hair loss, tender swollen nodes, or any boggy/pus-filled area.
- If you’re unsure—getting the right diagnosis ensures the right treatment.
Everyday tips
- Be gentle: avoid harsh scratching and hot blow-drying.
- Use products suited to your hair/skin type; fragrance-free if sensitive.
- Don’t share combs, brushes, or hats; clean hair tools regularly.