It is a clinical condition of skin characterized by rash which may be reddish, swollen or greasy and White or yellowish crusty scales affecting scalp, face, chest and shoulder region . Seborrheic dermatitis can look like psoriasis, eczema, or a skin allergy. In case of infants it is called cradle cap because the greasy crusty appearance of the scalp in infants looks like a cap.
Exact cause is somewhat contradictory. It may be due fungus (Malassezia), Genetic, environmental, hormonal, and immune-system factors, psychological stress, fatigue, sleep deprivation, change of season and reduced general health.
Note: We are giving only a brief description of each disease for your quick reference with some best related photographs where needed.