Seborrhea, or seborrheic dermatitis, refers to an inflammatory skin condition that is due to a combination of factors including the yeast Malassezia and immune-related factors. Its appearance ranges from mild dandruff to full body redness called erythroderma. It may be aggravated by changes in climate, skin trauma, or emotional stress. Patients with Parkinson’s disease and HIV may suffer from significant seborrheic dermatitis. Topical therapy is usually sufficient to control seborrhea. Antidandruff shampoos, topical prescription creams, and proper skin moisturizers all improve seborrheic dermatitis.