Seborrheic dermatitis is a skin condition that causes itchy red patches and greasy scales on your skin along with dandruff on your scalp. Dandruff is the result of skin cells on the scalp that grow and die off too fast, causing white or gray flakes to appear on the head and hair.
Causes
Seborrheic dermatitis is likely caused by the overgrowth of a yeast called malassezia, which is present on everyone’s skin, excess oil in the skin, or issues with the immune system. Dandruff is caused by the same factors, but additionally could be a result of an allergy or simply a lack of shampooing.