Seborrheic dermatitis shows up as red, inflamed patches of skin covered with greasy or flaky scales that are white to yellowish in color. It affects about 5.6% of adults and appears almost exclusively in areas with a high concentration of oil glands: the scalp, face, and chest. The pattern and location of these patches are actually the most important feature for identifying the condition.
What It Looks Like on the Scalp
On the scalp, seborrheic dermatitis ranges from mild flaking (what most people call dandruff) to thick, honey-colored crusts that stick to the scalp and hair. The key visual difference between ordinary dandruff and seborrheic dermatitis is redness. Dandruff produces light white or yellow flakes scattered through the hair with no visible inflammation underneath. Seborrheic dermatitis produces larger, oilier or drier scales sitting on top of clearly reddened, inflamed skin.
In more severe cases, the rash can creep past the hairline onto the forehead, forming a scaly, reddish border sometimes called a “corona,” which wraps along the edge of the hair. When the condition is persistent, it can even contribute to temporary hair thinning in affected areas.
The Typical Facial Pattern
Facial seborrheic dermatitis follows a very specific, symmetrical pattern. It targets the center of the face: the creases running from the nose to the corners of the mouth (the nasolabial folds), the sides of the nostrils, the middle of the forehead, and the inner portions of the eyebrows. The face is the single most common site, involved in roughly 88% of adult cases.
These areas look pink or red with a fine, slightly greasy scale on top. The rash tends to settle into skin folds and creases rather than spreading across flat, open areas of the cheeks or jaw. Because of this fold-hugging pattern, the rash can look almost like it was painted into the grooves of the face.
Behind the Ears and Inside the Ear Canal
The area behind the ears is a classic spot. It typically appears as a well-defined, reddish, scaly plaque right in the crease where the ear meets the head. The scaling can extend into the external ear canal itself, sometimes causing itching or a feeling of flaking inside the ear. The patches behind the ears often have a greasy crust and can crack or weep slightly if irritated.
Eyelid and Lash Line Involvement
Seborrheic dermatitis commonly affects the eyelids, a presentation called seborrheic blepharitis. You’ll notice oily, loose, flaky scales along the eyelid margin and around the base of the eyelashes. The eyelid skin may look slightly swollen and red. Scaling can also appear on the skin around the eyes and along the eyebrows. If you’ve noticed persistent, greasy flaking right at your lash line along with similar scaling in your eyebrows or nasolabial folds, these signs together point strongly toward seborrheic dermatitis rather than a simple eye irritation.
Chest and Body Patches
About 27% of adults with the condition develop patches on the chest, particularly over the breastbone. On the trunk, seborrheic dermatitis can take on distinctive shapes. Some people develop petal-like or arc-shaped patches, a presentation called petaloid seborrheic dermatitis. These patches have the same greasy scale and reddened base seen elsewhere on the body. Other common body sites include the skin folds of the groin and armpits, where warmth and moisture make the rash more pronounced.
How It Looks on Darker Skin Tones
The “classic” description of seborrheic dermatitis centers on redness, but that redness can be difficult to see on darker skin. Instead, people with deeper skin tones often notice lighter patches (hypopigmentation) in the affected areas, with flaking and scaling that may be more prominent than any color change. The patches can appear ashy or washed out rather than pink or red. Petal-shaped or arc-shaped patches on the trunk are also more commonly described in skin of color. Children with darker skin tones are less likely to show the typical cradle cap appearance and instead develop flaking and lightened patches in skin folds.
Cradle Cap in Infants
In babies, seborrheic dermatitis is most familiar as cradle cap. It appears as thick, crusty patches on the scalp that can be white or yellow, sitting on a reddened, inflamed base. When the patches are extensive, they can merge together into a continuous layer that looks like a cap covering the top of the head. The crusts tend to feel greasy rather than dry. In infants, the rash can also appear in the diaper area, the neck folds, and the armpits, where it looks like red, scaly patches in the creases of the skin.
How It Differs From Psoriasis
Seborrheic dermatitis is frequently confused with scalp psoriasis, and the two can even overlap. The practical visual difference comes down to scale quality and thickness. Psoriasis scales tend to be thicker, drier, and more silvery-white, with sharply defined borders. Seborrheic dermatitis scales are thinner, greasier, and more yellowish, with borders that blend more gradually into surrounding skin. Psoriasis also commonly extends beyond the scalp to the elbows, knees, and lower back, while seborrheic dermatitis stays loyal to oil-rich zones: the scalp, central face, ears, and chest.
Location within the scalp can also help. Seborrheic dermatitis tends to be more diffuse, while psoriasis often forms discrete, well-bordered plaques. When patches appear in the nasolabial folds and eyebrows alongside scalp flaking, seborrheic dermatitis is the more likely explanation.