Seborrheic Dermatitis

Seborrheic dermatitis is an inflammatory skin disorder that affects the scalp primarily, but can also affect the face and the torso in some cases. This condition favors the areas with a high concentration of sebaceous glands. It is often confused with moderate to severe cases of dandruff when it affects only the scalp region. Unlike dandruff, the inflammation on the skin is visible on the scalp. Called cradle cap, infants in their first three months also are often affected by a variant of this condition. This condition is not an infection, and cannot spread from person to person. The exact cause is not known, but there is often an overgrowth of naturally occurring yeast called Malassezia.

Key Symptoms:

Scalp involvement that itches in addition to flaking-scales larger than typical dandruff
Itching is often a major feature, as is redness and inflammation
Compared to dandruff, the scales clump more and are larger, and are often inflamed
Cradle cap, the variant that affects infant is self-limiting, and will disappear after a month or two without treatment
The condition can be controlled with medicated shampoos and topical medications, but often will be a problem at a later time
Unlike rosacea where redness is even and widespread, seborrheic dermatitis appears as rashes, and is itchy or sore

Seborrheic dermatitis and rosacea:

Seborrheic dermatitis can initially look similar to rosacea when the rashes affect the cheeks, and the area between the nose and the lips. In the majority of cases, however, seborrheic dermatitis affects the scalp before other areas of the face become involved, hinting at the condition.
A major feature of seborrheic dermatitis is inflammation and itching, which is not typical of rosacea. Both rosacea and seborrheic dermatitis are discomforting enough to warrant a visit to a dermatologist, and both conditions can be controlled relatively easily with topical treatments.