What it is
Seborrheic dermatitis (SD) is a common chronic inflammatory skin condition. On the scalp it causes yellow, greasy scales, redness, and itching. It's the medical version of "dandruff" — more intense, persistent, and with visible inflammation.
It's triggered by Malassezia yeast, a normal resident of oily skin areas. In SD, the immune system overreacts to Malassezia's byproducts, causing inflammation.
SD can flare during stress, cold weather, illness, or hormonal shifts. It's not caused by poor hygiene and isn't contagious.
Symptoms to recognize
- Yellow or off-white scales that stick to scalp and hair
- Greasy, oily-feeling scalp
- Red, inflamed patches (visible at the hairline, behind ears, around eyebrows)
- Itching that worsens with sweating or stress
- Sometimes temporary shedding in affected areas
If it appears on face too (eyebrows, sides of nose, beard), it's almost certainly SD.
Daily management
Active ingredients (rotating)
- Ketoconazole 2% (Nizoral) — gold standard, use 2x week, leave 3–5 min
- Ciclopirox 1% — alternative antifungal
- Selenium sulfide 2.5%
- Zinc pyrithione 1–2%
- Piroctone olamine — gentler, everyday use
Rotate 2 actives to prevent resistance. Example: Ketoconazole Mon/Thu, Zinc pyrithione Wed/Sat.
Supportive ingredients
- Salicylic acid — helps exfoliate scale
- Tea tree oil (low %, 2–5%) — antifungal support
- Niacinamide — reduces inflammation
- Colloidal oatmeal — soothes itch
What to avoid
- Coconut oil, olive oil — fatty acids feed Malassezia
- Butters on scalp (shea, mango)
- Heavy silicones that trap sebum
- Harsh sulfates that compromise skin barrier
- Skipping wash days — SD worsens with sebum buildup
Lifestyle factors
- Manage stress — a major flare trigger
- Sleep — poor sleep raises inflammation
- Diet — some benefit from reducing high-glycemic foods and dairy (evidence is mild but real)
- Sun exposure — mild sun often helps (UVB reduces Malassezia); protect skin but get daily outdoor time
When to see a dermatologist
- Flares lasting more than 6 weeks despite OTC actives
- Painful, bleeding, or scabbed areas
- Hair loss where flakes appear
- Pruritus disturbing sleep
- Lesions spreading to face or body
Prescription options include stronger antifungals, topical steroids (short courses), and calcineurin inhibitors (pimecrolimus) for sensitive areas.
Long-term expectations
SD is chronic — meaning it's managed, not cured. With a consistent routine most people achieve "flake-free" status within 4–6 weeks. Flares typically return 2–4 times a year; stay ready with medicated shampoo on hand.
Matching product to severity
Mild SD can be managed with a good daily mild shampoo + medicated 1–2x per week. Moderate needs medicated more often + supportive serums. Severe needs prescription.
The Mutaly quiz flags seborrheic tendency and routes you to treatment shampoos appropriate for your hair type (some medicated formulas are drying for color-treated or damaged hair — we adjust).