Seborrheic dermatitis is a chronic inflammatory skin condition characterized by red, itchy, and flaky patches. It commonly affects areas rich in sebaceous glands, such as the scalp, face, and upper chest. The exact cause is unknown, but it is associated with the overgrowth of yeast on the skin and may be exacerbated by stress, cold weather, and hormonal changes. Treatment includes antifungal medications, topical corticosteroids, and medicated shampoos.