Seborrheic Dermatitis www.lifescript.com/health/a-z/mayo/s/seborrheic_dermatitis.aspx. A yeast (fungus) called malassezia that is in the oil secretion on the skin; An inflammatory response ... If your scalp is affected, a nonprescription antifungal shampoo may ease your symptoms ... area, because if you irritate your skin or scratch it open, you increase your risk of infection. ... Seborrheic Dermatitis www.lifescript.com/health/a-z/conditions_a-z/conditions/s/seborrheic_dermatitis.aspx.