Seborrhea is a fungal infection and inflammation of the hair follicles a mild case could just be dandruff. Severe cases can cause red, itchy, flaky even a yellow crust on the skin. Usually in areas with many hair follicles or sweat glands, Face, underarms, chest etc. If it's a severe case it's best to see a doctor an anti fungal shampoo may be prescribed, or it could just be something in your diet. For a mild case try an anti dandruff shampoo.