The cause of seborrheic dermatitis is complex. It is an inflammatory condition that occurs on the basis of seborrhea and may be related to increased sebum production or changes in its chemical composition. However, the exact cause of seborrheic dermatitis is not known. Microorganisms that live on the skin such as fungi may also cause seborrheic dermatitis. Seborrheic dermatitis is not the result of an infection and is not contagious. People of any age can develop seborrheic dermatitis, including infants, and it is more common in men than in women. The disease tends to be confined, initially on the head, and in aggravated cases may progress to the face, behind the ears, armpits, upper chest, interscapular region, umbilicus, vulva and groin. The initial lesion is a perifollicular inflammatory papule, and as the disease progresses, the papules fuse into yellow-red patches of varying size with clear borders, covered with greasy scales or crusts. Due to the location and severity of the damage, the bed manifestation also differs. The light damage on the head is small grayish-white chaffy or greasy scaly patches with a flushed base. In severe cases, it involves most of the scalp and is covered with greasy crusts, which may exude and have a fishy odor. Seborrheic dermatitis is a relatively common disease, but not an infectious disease. With proper treatment, it can also be cured.