Seborrheic Dermatitis

Seborrheic dermatitis is a common form of dermatitis (inflamed skin) that shows up in oily areas of the body. These include the scalp, eyebrows, sides of the nose, ears, and chest. It causes flaky scales, greasy patches, and mild redness.

On the scalp, a mild version is what most people call dandruff. The two are part of the same process, just different in degree.

Seborrheic dermatitis tends to come and go. It often flares in cold, dry months and calms in summer. It is not caused by poor hygiene, and it is not contagious. In babies, it appears as "cradle cap," a scaly, crusty patch on the scalp that usually clears on its own.

The main signs are flaking and mild redness in oily areas:

• White or yellowish flakes (dandruff) in the hair and on the shoulders.
• Greasy patches covered with scale, often on the scalp, eyebrows, sides of the nose, and ears.
• Skin that looks red or pink on lighter skin. On darker skin, patches may look darker or lighter than the surrounding skin, and redness can be harder to see.
• Mild itching or burning.
• Ring-shaped or patchy scaling on the chest in some people.

Symptoms often flare and fade over time.

• Dandruff: The mildest form, limited to the scalp. It causes flaking and mild itch without much redness. Dandruff and seborrheic dermatitis are the same basic process on a spectrum.
• Scalp seborrheic dermatitis: More than dandruff, with greasy scale, redness, and itch on the scalp.
• Facial seborrheic dermatitis: Affects the eyebrows, sides of the nose, and beard area, with flaking and redness.
• Cradle cap: The infant form, a scaly, crusty patch on a baby's scalp. It is harmless and usually clears within months.
• Body seborrheic dermatitis: Scaly patches on the chest, ears, or skin folds.

Seborrheic dermatitis does not have one single cause. Doctors think a few things work together:

• Malassezia yeast: This is a yeast (a type of fungus) that lives on everyone's skin. In seborrheic dermatitis, the skin overreacts to it, which leads to inflammation and flaking.
• Skin oil (sebum): The condition appears where oil glands are most active. The yeast feeds on this oil.
• An overactive immune response: The skin reacts more strongly to the yeast than it should.
• Personal factors: Genes, hormones, stress, cold weather, and certain health conditions can all play a role.

It is not caused by being dirty, and washing alone does not fix it.

Triggers can set off a flare. Common ones include:

• Cold, dry weather (winter flares are common)
• Stress and being run-down
• Not washing oily areas often enough
• Hormonal changes
• Certain medical conditions (such as Parkinson's disease or a weakened immune system)
• Some medications
• Harsh or drying skin products

A doctor or dermatologist can usually diagnose seborrheic dermatitis by looking at the skin and asking about your symptoms. The location (oily areas), the greasy scale, and the pattern of flaring often make it clear.

No special lab test is needed in most cases. If the diagnosis is unclear, or the skin does not respond to treatment, a doctor may take a small skin sample (biopsy) or check for other conditions like psoriasis or a fungal infection.

Most cases are controlled with medicated shampoos and gentle skin care. The goal is to reduce yeast, oil, and flaking.

• Medicated shampoo: Use an over-the-counter dandruff shampoo. Helpful active ingredients include ketoconazole, zinc pyrithione, selenium sulfide, salicylic acid, and coal tar. Leave it on for several minutes before rinsing.
• Rotate shampoos: Switching between two types can keep them working well.
• Use on the face and body too: Some medicated shampoos can be used briefly on the face or chest, then rinsed. Check the label first.
• Do not scrub or pick: This can make redness worse.
• Soften scale: For thick scale or cradle cap, a little mineral oil can loosen it before washing.
• Manage triggers: Reduce stress where you can, and keep up a steady routine even after the skin clears.

Look for medicated shampoos and washes made to fight flaking and the yeast behind it. The most useful active ingredients are ketoconazole, zinc pyrithione, selenium sulfide, salicylic acid, and coal tar. Many people do best rotating between two different shampoos so the skin does not get used to just one. For the face, choose gentle, fragrance-free cleansers and light, non-greasy moisturizers, and use medicated products as directed.

If over-the-counter care is not enough, a dermatologist may prescribe:

• Prescription antifungal shampoos or creams: Stronger ketoconazole or ciclopirox to lower the yeast.
• Topical steroids: Short-term anti-inflammatory creams or lotions to calm redness and itch during flares.
• Topical calcineurin inhibitors: Steroid-free creams (such as tacrolimus and pimecrolimus), often used on the face where long-term steroid use is best avoided.
• Medicated foams or solutions made for the scalp.
• Oral antifungal pills: Rarely, for severe or widespread cases.

These are often used short-term to control a flare. Maintenance then shifts back to medicated shampoo.

Seborrheic dermatitis is treated with shampoos and creams, not procedures. In-office treatments are rarely needed, though phototherapy (controlled ultraviolet light in a clinic) is sometimes considered for widespread, stubborn cases.

See a dermatologist if medicated shampoos and OTC care do not control the flaking and redness; the skin becomes very red, swollen, painful, or looks infected; the rash spreads or is severe; you are unsure whether it is seborrheic dermatitis or another condition like psoriasis; or a baby's cradle cap looks infected or spreads widely.

A few conditions can look like seborrheic dermatitis:

• Psoriasis: Thicker, well-defined patches with silvery scale. Scalp psoriasis can look very similar, and an overlap called "sebopsoriasis" exists.
• Atopic dermatitis (eczema): Itchy, dry, inflamed skin, but usually in the bends of the elbows and knees rather than oily areas.
• Rosacea: Facial redness and bumps, without the greasy flaking.
• Fungal infections (tinea): Ring-shaped, spreading rashes that need antifungal treatment.
• Contact dermatitis: A rash from a product or irritant touching the skin.

Because these overlap, it is worth getting a diagnosis if the skin does not improve.