Dandruff and Seborrheic Dermatitis: Causes and Treatment

Dandruff is the mildest form of seborrheic dermatitis, a common long term skin condition where the scalp reacts to Malassezia, a yeast that naturally lives on oily skin. It cannot be cured once and for all, but antifungal medicated shampoos, used correctly and regularly, control it well for most people.

In India, dandruff often gets worse in winter, flares with stress and exam season, and is frequently aggravated by a well meaning habit: leaving oil on the scalp overnight. Here is what is really going on and how to manage it.

What causes dandruff and seborrheic dermatitis?

Three things come together:

• Sebum (scalp oil). Seborrheic dermatitis appears where oil glands are most active: scalp, eyebrows, sides of the nose, behind the ears, beard, chest and upper back.
• Malassezia yeast. It lives on almost everyone’s skin and feeds on oil. In some people, the by-products of this yeast trigger inflammation.
• Individual sensitivity. Genes, stress, sleep, climate and general health affect how strongly your skin reacts.

Flares are common with:

• Cold, dry weather and indoor heating
• Stress, poor sleep and illness
• Infrequent washing, especially with heavy oil use
• Conditions such as Parkinson disease, HIV and some neurological conditions, where seborrheic dermatitis can be more severe

It is not caused by poor hygiene, and it is not contagious.

What does it look like?

• Mild (dandruff): white or yellowish flakes on the scalp and shoulders, with mild itch.
• Moderate to severe: red patches with greasy yellow scale on the scalp, eyebrows, the folds beside the nose, behind the ears, and in the beard. On brown skin, the patches can look darker or lighter rather than red.
• Infants: cradle cap, thick yellow crusts on a baby’s scalp, which is usually harmless and settles.

Is it dandruff, psoriasis or a fungal infection?

Several conditions cause a flaky scalp, and they are treated differently.

Condition	What it looks like	Key clues
Dandruff or seborrheic dermatitis	Greasy, yellowish flakes, mild redness	Eyebrows, nose folds, behind ears also involved
Scalp psoriasis	Thick, silvery, well defined plaques	Often extends past the hairline, plaques on elbows, knees or nails
Tinea capitis (scalp ringworm)	Scaly patches with broken hairs, sometimes swelling	Mostly in children, may spread in families
Contact dermatitis	Itchy, red, sometimes oozing	Starts after hair dye, henna mixes or new products
Dry scalp	Fine white flakes, no oiliness	Better with gentle washing and conditioner

If you have thick plaques, see our guide on psoriasis symptoms and treatment. Scalp ringworm needs oral antifungal treatment, not shampoo alone; read more on fungal infections in India.

How do I treat dandruff at home?

The most important step is using a medicated shampoo the right way.

Choose an active ingredient. Common options available in India include:

• Ketoconazole
• Zinc pyrithione
• Selenium sulfide
• Ciclopirox
• Coal tar
• Salicylic acid, which helps lift thick scale

Use it correctly:

1. Wet the hair and massage the shampoo into the scalp, not just the lengths.
2. Leave it on for about 5 minutes before rinsing. This contact time is what lets the antifungal work.
3. Use it two to three times a week at first.
4. Once controlled, continue once a week or so to prevent relapse.
5. Use a regular conditioner on the lengths if the medicated shampoo feels drying.

If one ingredient stops working well, rotating between two different actives can help.

People with tightly coiled or very dry hair may prefer washing once a week with a medicated shampoo and using a scalp-friendly conditioner, as advised by the AAD.

Does hair oiling help or harm dandruff?

This is one of the most common questions we hear. Traditional champi feels good and can help dry, frizzy hair lengths, but on a scalp with seborrheic dermatitis:

• Plant oils, especially those rich in certain fatty acids, can feed Malassezia.
• Oil left overnight or for days traps scale and sweat in humid weather.
• Many patients notice more itching and flaking after oiling.

If you do not want to give up oiling, apply it to the lengths, keep scalp contact short, and wash with your medicated shampoo the same day.

What about face, eyebrows and beard?

Seborrheic dermatitis often appears on the face as flaky, red or darkened patches beside the nose, in the eyebrows and in the beard. Your dermatologist may suggest:

• Washing the area with the medicated shampoo as a face wash for a minute, then rinsing.
• Antifungal creams.
• Short courses of mild anti-inflammatory creams or non-steroid options such as calcineurin inhibitors, prescribed and supervised.

Please do not use over the counter steroid creams on your face for flaking. They may seem to help briefly but can cause thinning, redness and rebound flares. Our article on topical steroid misuse explains why.

Do hard water, humidity or pollution make dandruff worse?

Many people in Indian cities notice their dandruff changes with the season or after moving to a new place. Here is what we know:

• Humidity and sweat during summer and the monsoon keep the scalp damp and oily, which suits Malassezia. Washing after heavy sweating helps.
• Cold, dry winters in North India are a classic flare season, partly because people wash less often and the skin barrier dries out.
• Hard water can leave mineral deposits that make hair feel rough and shampoo lather poorly. It does not cause seborrheic dermatitis, but it may make the scalp feel more irritated. A clarifying wash now and then and a good conditioner on the lengths can help.
• Pollution and dust settle on the scalp and mix with oil, so regular washing matters more for people who commute in traffic or work outdoors.
• Helmets and caps trap heat and sweat. They do not cause dandruff, but wiping the inner lining and washing the scalp after long rides helps.

None of these are reasons to stop washing your hair. In fact, most people with dandruff do better with more frequent washing, not less.

What treatments might a dermatologist add?

For stubborn or severe seborrheic dermatitis, your dermatologist may consider:

• Prescription strength antifungal shampoos or lotions
• Short, supervised courses of anti-inflammatory scalp lotions to settle a flare
• Calcineurin inhibitor creams for the face
• Oral antifungal medicines in selected cases
• Checking for associated conditions if it is unusually severe or sudden

Can diet or lifestyle make a difference?

Evidence linking specific foods to dandruff is weak. Sensible steps that help many people:

• Wash your scalp regularly, especially after sweating or gym sessions.
• Manage stress and get enough sleep.
• Avoid heavy pomades and styling products on the scalp.
• Do not share combs if there is any chance of scalp ringworm in the family, particularly with children.

When to see a dermatologist

Book a review if:

• Flaking and itch continue after four weeks of correct medicated shampoo use.
• The scalp is very red, weeping, crusted or painful.
• You notice patchy hair loss, broken hairs or swollen lymph nodes in the neck.
• Thick, silvery plaques appear, or nails change.
• A child has a scaly scalp with hair loss.
• The rash spreads to the face, chest or folds.

With the right diagnosis, dandruff is usually very manageable. Dr. Maria offers online consultations where she can look at photos of your scalp and suggest a routine that suits your hair.