Seborrheic Dermatitis

What seborrheic dermatitis is

Areas rich in oil (sebaceous) glands support large numbers of Malassezia yeasts. These yeasts break down skin oils into fatty acids. In some people, the skin reacts to these products with inflammation and faster skin turnover, producing redness and scale. The yeast itself is normal; what differs is the skin's response. Genes, skin barrier function, hormones and the immune system all play a part.

It is one of the most common skin conditions, affecting a few percent of adults with visible rash and far more with dandruff alone.

Symptoms by area

Scalp

Ranges from fine white flakes (dandruff) to thick, greasy, yellowish scale with redness along the hairline, behind the ears and in the ear canals. It is often itchy. Severe scalp involvement can cause temporary hair shedding, which regrows with treatment.

Face

Seborrheic dermatitis on the face appears as redness and fine scale in the creases beside the nose, between and on the eyebrows, on the forehead, in the beard and mustache, and around the ears. It often flares in winter and with stress. Eyelid edges can be crusty and irritated (blepharitis).

Chest, back and body folds

Pink or brown, slightly scaly patches in the center of the chest or between the shoulder blades, sometimes ring-shaped. Moist, red patches can form in armpits, under the breasts and in the groin.

On darker skin

Patches may look lighter (hypopigmented) or darker than surrounding skin rather than red, and can appear as ring-shaped or petal-like patches along the hairline, particularly in Black children and adults. Frequent washing advice needs tailoring for tightly coiled hair (see below).

In babies

Cradle cap causes thick, yellow, greasy scales on the scalp in the first months of life, sometimes spreading to the eyebrows, behind the ears and the diaper area. It is not itchy and usually clears by 6 to 12 months.

Causes and triggers

• Malassezia yeast on the skin and the skin's inflammatory response to it
• Stress and fatigue
• Cold, dry weather; many people improve in summer
• Hormonal changes
• Harsh soaps, alcohol-based toners and some hair products
• Illness or recovery from a major illness
• Some medicines, such as certain psoriasis treatments, lithium and interferon (uncommon)

Conditions linked to more severe disease

• Parkinson's disease and other nerve conditions, possibly through increased oil production and reduced facial movement
• HIV infection: severe or sudden-onset seborrheic dermatitis can be an early sign
• Depression, stroke, heart failure and alcohol use disorder
• Down syndrome
• Acne and rosacea, which share the same skin areas

Seborrheic dermatitis vs psoriasis and other rashes

Some people have features of both seborrheic dermatitis and psoriasis, sometimes called "sebopsoriasis".

Diagnosis

A doctor or dermatologist usually diagnoses seborrheic dermatitis by looking at the skin and the pattern of areas involved. Tests are needed only when the picture is unusual: a skin scraping for fungus, a biopsy if psoriasis or lupus is suspected, or an HIV test for sudden, severe cases.

Treatment

The goal is control. Most people need a treatment phase to clear the rash and then a maintenance routine to keep it away.

Scalp

• Medicated shampoos used 2 to 3 times a week, left on for about 5 minutes before rinsing: ketoconazole, selenium sulfide, zinc pyrithione, ciclopirox, salicylic acid or coal tar. Rotating two types can help.
• For thick scale: apply mineral oil or a salicylic acid product, leave it on for a few hours, then wash out.
• For itching and inflammation: a short course of a steroid solution, foam or shampoo (such as clobetasol shampoo) prescribed by a doctor.
• For tightly coiled or textured hair: washing once a week with a medicated shampoo is often enough, combined with scalp-applied antifungal or steroid products, to avoid dryness and breakage.

Face and body

• Antifungal creams: ketoconazole or ciclopirox, once or twice daily.
• Low-strength steroid creams (such as hydrocortisone) for short periods during flares. Avoid long-term use on the face, which thins skin and can cause rosacea-like rashes.
• Non-steroid options: topical calcineurin inhibitors (tacrolimus, pimecrolimus) and roflumilast foam, approved for seborrheic dermatitis, are useful for longer-term use on the face.
• Gentle cleansing: a mild cleanser, or a dandruff shampoo used as a face wash for a minute, then rinsed.

Eyelids

Warm compresses and gentle cleaning of the lid margins with diluted baby shampoo or lid wipes. Ask a doctor before using any steroid near the eyes.

Babies with cradle cap

Gently massage baby oil or mineral oil into the scalp, wait 15 minutes, loosen scales with a soft brush and wash with mild baby shampoo. Do not pick scales. See a doctor if it spreads, looks inflamed or the baby is unwell.

Severe or stubborn cases

Oral antifungal tablets (such as itraconazole), phototherapy, or treatment of an underlying condition may be considered by a dermatologist.

Outlook and prevention of flares

Seborrheic dermatitis in adults is long-term and tends to come and go. It does not cause permanent hair loss or scarring and is not linked to cancer. To keep it under control:

• Keep using a medicated shampoo or cream once or twice a week once clear.
• Wash oily areas regularly and rinse soap fully from the skin and beard.
• Avoid alcohol-based lotions and heavy, greasy hair products.
• Manage stress and get enough sleep.
• Restart treatment at the first sign of flaking.

Frequently asked questions

What causes seborrheic dermatitis?

It is caused by an inflammatory reaction of the skin to Malassezia, a yeast that normally lives on oily skin, combined with genetic and immune factors. Flares are triggered by stress, cold dry weather, illness and harsh skin products. It is not caused by poor hygiene and is not contagious.

How do you get rid of seborrheic dermatitis on the face?

Use an antifungal cream such as ketoconazole or ciclopirox once or twice daily, plus a short course of a mild steroid cream during flares. For long-term control, non-steroid creams like tacrolimus or roflumilast foam help. Washing with a dandruff shampoo as a face wash a few times a week can prevent flares.

Is seborrheic dermatitis the same as dandruff?

Dandruff is the mildest form of seborrheic dermatitis, with flaking but little or no redness. Seborrheic dermatitis can also cause red, inflamed, greasy patches on the scalp and on the face, ears and chest. Both respond to the same antifungal shampoos.

What is the difference between seborrheic dermatitis and psoriasis?

Seborrheic dermatitis has greasy, yellow-white scale with fuzzy edges and favors oily areas such as the nose folds and eyebrows. Psoriasis forms thicker, silvery, sharply outlined plaques, often on elbows, knees and the lower back, and can affect the nails. Some people have overlapping features.

Can seborrheic dermatitis be cured?

In babies, cradle cap almost always clears for good within the first year. In adults it is usually long-term, but it can be controlled well with regular use of medicated shampoos or creams, and many people have long symptom-free periods.

Does seborrheic dermatitis cause hair loss?

Severe scalp inflammation and scratching can cause temporary hair shedding, but seborrheic dermatitis does not cause permanent baldness. Hair usually regrows once the inflammation is controlled. Patchy hair loss with scale in children should be checked for a fungal infection.