What is seborrhoeic dermatitis?

Seborrhoeic dermatitis is a common inflammatory skin condition that tends to flare on areas rich in oil glands — most often the scalp, but also the eyebrows, sides of the nose and chest. On the scalp it causes flakes that may look white or yellowish, itching that can be persistent, and patches of redness that sometimes feel sore or tight. It is not a sign of poor hygiene, and it is not contagious. The underlying trigger is an overreaction to Malassezia, a yeast that lives harmlessly on most people’s skin. When the scalp’s barrier is stressed — by cold weather, stress, illness or certain products — the immune system responds with inflammation, and the cycle of flaking and itching begins.

First-line treatment: medicated shampoos

For most people, the cornerstone of scalp seborrhoeic dermatitis is an antifungal shampoo, not a steroid. These reduce the yeast load and calm the inflammatory response. Useful options include:

• Ketoconazole 1% (over the counter) or 2% (prescription) — apply to wet scalp, lather, and leave for 5–10 minutes before rinsing.
• Selenium sulphide — helps slow yeast growth and loosen flakes; follow the same leave-on time.
• Zinc pyrithione — a gentle antifungal often found in everyday anti-dandruff shampoos.
• Coal tar or salicylic acid — useful for stubborn scale, but can be drying, so alternate with a gentler product.

Use a medicated shampoo two to three times a week for the first few weeks, then taper to once weekly or fortnightly to keep flakes at bay. It helps to rotate between two different active ingredients every few months, as the scalp can become tolerant to one. Leave the shampoo in contact with the scalp for the full recommended time — quick rinses are far less effective.

When topical steroids have a role

Topical steroids do not treat the yeast, but they are very effective at damping down redness, itching and soreness during a flare. They are best used as a short-term add-on to antifungal treatment, not as a standalone fix. For the scalp, a mild to moderate potency steroid — such as hydrocortisone 1% or a scalp application of betamethasone valerate — is usually enough. Apply a thin layer to the affected areas once or twice daily for no more than one to two weeks, then stop. Prolonged use can thin the skin, cause rebound flares when stopped abruptly, and mask infection. If you need a steroid more than a few times a month, speak to your GP or pharmacist about adjusting your antifungal routine instead.

Gentle scalp care that makes a difference

Harsh handling can worsen inflammation, so treat your scalp like sensitive skin. Wash regularly — skipping washes lets oil and yeast build up. Use lukewarm water, not hot. Choose a gentle, fragrance-free shampoo for non-treatment days, and avoid scratching, picking or scraping flakes with combs. Pat hair dry rather than rubbing vigorously. Limit styling products, dyes and relaxers, which can irritate. Some people find that sun exposure helps, but never allow your scalp to burn. Stress is a well-known trigger, so build in simple relaxation where you can. If you use conditioner, apply it to the ends of your hair only, keeping it off the scalp.

Building a realistic daily routine

A practical week might look like this: on Monday, Wednesday and Friday, use your medicated antifungal shampoo, leaving it on for the full time. On other days, use a gentle shampoo if you want to wash. If itching and redness flare, add a thin layer of prescribed or over-the-counter hydrocortisone scalp lotion for three to five days, then stop. Keep a simple diary of flares and possible triggers — cold snaps, stressful weeks, new hair products — so you can spot patterns. Improvement often takes two to four weeks, so be patient. Once clear, do not stop everything; continue a maintenance antifungal wash once a week or fortnight to prevent relapse.

When to seek professional advice

See your pharmacist or GP if there is no improvement after four weeks of consistent antifungal shampoo use, if the scalp becomes very painful, weepy or crusted, or if you notice hair loss or signs of infection such as pus or spreading redness. A doctor can confirm the diagnosis — seborrhoeic dermatitis can look similar to psoriasis or eczema — and prescribe stronger treatments if needed. If you have tried several products without success, ask for a referral to a dermatologist. With the right combination of antifungal care, short-term anti-inflammatory treatment and gentle scalp habits, most people can keep flakes, itching and redness comfortably under control.