Seborrheic dermatitis (Seb derm) is a very common, scaly rash that tends to occur in areas where the skin is oily: scalp (dandruff), eyebrows, eyelids, ears, sides of the nose (nasal folds), armpits, central chest, and groin.
Seborrheic dermatitis is believed to be caused by an overabundance of skin yeast (Malassezia). This yeast is found normally on most people's skin. Seborrheic dermatitis is NOT contagious, but it appears to run in families. The yeast produces substances that can irritate the skin and make it red and itchy. Sometimes there can be discoloration in the form of hyperpigmentation or hypopigmentation resulting from this condition.
Seborrheic dermatitis is typically NOT associated with any worrisome condition. Stress, physical illness, and hospitalization can lower an individual's resistance to the yeast, making the seborrheic dermatitis worsen or flare. There are some immune conditions (like HIV) and neurological conditions (like Parkinson's disease) that are associated with seborrheic dermatitis in some instances. For most patients, there is no need to perform laboratory or allergy tests, unless the seborrheic dermatitis is not controlled with treatment.
Cradle cap, seen in babies up to 6 months of age, is thought to be an infantile form of seborrheic dermatitis. The scalp, armpits, and groin are typically affected. It is usually not bothersome or itchy for the infant even when it looks severe. Cradle cap can be treated by letting mineral oil sit on the thick scale for 20-30 minutes followed by baby shampoo and gentle massage to the scalp. Cases that do not resolve easily sometimes require a prescription medication prescribed by your dermatologist.
Seborrheic dermatitis is a CHRONIC condition that can appear any time, usually after puberty. The condition fluctuates in severity, and may persist indefinitely. This condition is often easily controlled with medications. However, each patient often needs a plan that is unique to their hair type, ethnic background, and severity. Seborrheic dermatitis often requires a maintenance treatment to lessen flares and a rescue medication when a flare occurs. The regularity of maintenance needed can range from daily to once per week depending on the patient and their lifestyle.