Seborrheic dermatitis/ eczema or commonly called dandruff is a common skin disorder characterized by itchy, red skin covered with white or yellow greasy scales.
The areas rich in sebaceous glands are more commonly affected by this condition like the scalp, along the hairline, behind the ears, in the ear canal, on the eyebrows, around the nose, and/or on the chest.
The exact cause of Seborrheic dermatitis is not known. Multiple factors can contribute to this condition
Specific treatment for Seborrheic dermatitis will be determined by your physician. Commonly used medicines include Anti-fungal shampoos, Oral anti-fungals and topical corticosteroid lotions or creams and moisturizers. But though the condition responds to treatment, it may recur
Read more-
http://www.mayoclinic.org/diseases-conditions/seborrheic-dermatitis/basics/definition/con-20031872
http://www.webmd.com/skin-problems-and-treatments/seborrheic-dermatitis-medref
