Seborrheic dermatitis is a very common, scaling rash that tends to occur in areas where the skin is oily. Commonly affected areas include the scalp (dandruff), eyebrows, eyelids (blepharitis), ears, nasal folds, armpits, and groin. It is a chronic condition that can appear any time after puberty, fluctuates in severity, and may persist indefinitely. 

It is believed that seborrheic dermatitis is caused by an overabundance of a normally harmless skin yeast (malassezia). The yeast produces toxic substances that irritate the skin and make it itch. Stress and physical illness can lower an individual’s resistance to the yeast.

Seborrheic dermatitis is not contagious, but it appears to run in families.

On the scalp, seborrheic dermatitis appears as dry pink or flesh-colored patches with a yellow scaly surface. The patches may spread to the entire scalp. 

Infantile seborrheic dermatitis (“cradle cap”), seen in babies up to 6 months of age, is thought to possibly be the same condition. The scalp, armpits, and groin are typically affected.

Treatment options for seborrheic dermatitis include topical steroids, tar cream, and antifungal agents, often in the form of medicated shampoos. Cradle cap can be treated by using daily shampoos with a gentle cleanser and massage with mineral oil. Cases that do not resolve at times require a prescription topical medication.

It is important for those with seborrheic dermatitis to realize that they will likely need to have a maintenance routine to keep the rash for returning.  Usually, washing with a anti-dandruff shampoo a few times each week will help keep the yeast counts low and keep the rash from returning.  Occasionally, some individuals will need to use a prescription shampoo 1-2 times each week indefinitely.