Seborrheic dermatitis, often called “seb derm,” is a common inflammatory skin condition that causes oily, scaly patches on areas of your body that produce the most oil. It affects roughly 4.4% of the global population, and its mildest form on the scalp is what most people know as dandruff. It’s chronic, meaning it tends to come and go, but it’s manageable with the right approach.
What It Looks Like
The hallmark of seb derm is greasy-looking patches of skin covered with flaky white or yellow scales. These patches can be mildly irritating or intensely itchy, depending on the severity. On lighter skin, the affected areas tend to look red. On darker skin tones, patches may appear lighter or darker than the surrounding skin, which sometimes leads to misdiagnosis.
A less common variant called petaloid seborrheic dermatitis produces ring-shaped patches, almost like overlapping flower petals on the skin.
Where It Shows Up
Seb derm favors areas rich in oil glands. The face, scalp, and chest are the most common sites, showing up in roughly 88%, 70%, and 27% of cases, respectively. On the face, it tends to be symmetrical and concentrated in the center: the forehead, eyebrows (especially the inner edges), the creases beside your nose, and around the ears. It can also appear on the eyelids, causing a crusty buildup along the lash line.
Beyond the face and scalp, seb derm can develop in skin folds: the armpits, groin, and under the breasts. People with beards or mustaches often get flares in their facial hair, since those areas trap oil and create a favorable environment for the condition.
What Causes It
Seb derm isn’t caused by poor hygiene. The primary driver is a type of yeast that naturally lives on everyone’s skin. Two species in particular thrive in oily areas and feed on the fats your skin produces. They break down the oils using enzymes called lipases, and in the process, they leave behind certain fatty acids, especially oleic acid. Oleic acid penetrates the outer layer of skin, triggers inflammation, and causes the characteristic flaking.
The yeast also produces byproducts that activate your immune system’s first line of defense, creating a cycle: the yeast irritates the skin, the immune system responds with inflammation, and the resulting flaking and oil changes feed the yeast further. This is why seb derm is chronic rather than something you catch and get over.
Who Gets It and Why
Adults are more commonly affected than children, with a prevalence of about 5.6% in adults compared to 3.7% in children. Men develop it more often than women, likely because androgens (male hormones) increase oil production.
Several conditions raise your risk. Seb derm is notably more common in people with Parkinson’s disease, HIV, depression, and Down syndrome. The connection with neurological conditions may relate to changes in oil production controlled by the nervous system, though the exact link isn’t fully understood.
Flare Triggers
Stress is the single most consistent trigger. In one study comparing flare periods to stable periods in the same patients, a high stress level in the preceding month increased the odds of a flare by 4.5 times. Regular alcohol consumption was associated with a tenfold increase in flare risk in the same study, though the relationship was borderline statistically. Many people report worse flares in winter, though research hasn’t confirmed a clear seasonal pattern across larger populations. Smoking history also appears to raise the risk of flares.
Seb Derm in Babies (Cradle Cap)
In infants, seb derm is called cradle cap. It typically appears within the first three months of life as thick, greasy, yellowish scales on the top and front of the scalp. It looks alarming but is harmless, doesn’t bother the baby, and clears up on its own within a few weeks to months without treatment. In some infants, it can also appear in the diaper area and skin folds of the neck and armpits.
How It Differs From Psoriasis
Scalp psoriasis and seb derm can look similar, and they sometimes overlap in a condition informally called “sebopsoriasis.” A few differences help tell them apart. Psoriasis scales tend to be thicker, drier, and more silvery-white, while seb derm scales are oilier and yellowish. Psoriasis plaques often extend past the hairline onto the forehead and behind the ears, while seb derm usually stays within the hairline on the scalp. Psoriasis is also more likely to show up on elbows, knees, and nails, which seb derm doesn’t affect.
Over-the-Counter Treatments
For mild seb derm, especially on the scalp, medicated shampoos are the first step. Several active ingredients are available without a prescription, and they work through different mechanisms, so if one doesn’t help, another might:
- Zinc pyrithione (found in Head & Shoulders and others): reduces yeast and flaking. Also available as a bar soap for face and body use.
- Selenium sulfide (Selsun Blue and others): slows skin cell turnover and has antifungal properties.
- Ketoconazole 1% (Nizoral A-D): an antifungal that directly targets the yeast involved.
- Coal tar (Denorex, DHS Tar): reduces inflammation and slows scaling.
- Salicylic acid (Denorex, DHS Sal): helps loosen and remove scales so other treatments penetrate better.
For scalp flares, leave the shampoo on for several minutes before rinsing. If you have facial hair, shampooing your beard or mustache with a ketoconazole-based product daily during flares can make a real difference, since seb derm tends to be worse under facial hair.
Prescription Options
When over-the-counter products aren’t enough, prescription-strength treatments step up in potency. A 2% ketoconazole shampoo, gel, or foam is one of the most widely used options and is approved for moderate to severe scalp seb derm. For facial and body patches, prescription antifungal creams work alongside mild to moderate-strength steroid creams or ointments that calm inflammation quickly.
Steroid creams are effective for flares but aren’t ideal for long-term use, especially on the face, where they can thin the skin over time. An alternative for sensitive areas like the face and eyelids is a class of non-steroidal creams (calcineurin inhibitors) originally developed for eczema. These reduce inflammation without the thinning risk and also have some antifungal activity against the yeast involved in seb derm. They’re used off-label but have strong evidence supporting them.
For severe or stubborn cases that don’t respond to topical treatments, oral antifungal medications or light therapy may be considered.
Living With a Chronic Condition
Seb derm isn’t curable, but most people find a routine that keeps it well controlled. The key is recognizing that treatment doesn’t stop when a flare clears. Continuing to use a medicated shampoo or wash a few times per week, even during calm periods, helps prevent the yeast from building back up. Many people rotate between two different active ingredients to avoid the skin adapting to one.
Managing stress, moderating alcohol, and keeping oily areas clean are the lifestyle levers with the most evidence behind them. Flares will still happen, sometimes without an obvious trigger, but they tend to become less disruptive once you know the pattern and have a treatment plan ready.