Seborrheic dermatitis is a common skin disorder that can usually be treated fairly easily. Thought of as an inflammatory dandruff-like eruption, this condition is a red, scaly, itchy rash most commonly seen on the scalp, sides of the nose, eyebrows, eyelids, skin behind the ears, and middle of the chest. Other areas, such as the navel (belly button), buttocks, skin folds under the arms, axillary regions, breasts, and groin, may also be involved.