Doctors don't yet know the cause of seborrheic dermatitis. Factors that may play a role include:

  • A yeast (fungus) called Malassezia. This fungus is one of the normal microscopic life forms that grow, along with certain bacteria, in your skin's oily secretion (sebum). Creams, foams or lotions containing an antifungal agent, such as ketoconazole (Ketozole, Extina), often help reduce flare-ups, supporting the idea that this yeast is a contributing factor. But seborrheic dermatitis itself isn't considered an infection, and it's not contagious.
  • Change of season. Episodes are often worse in winter.
  • Neurological conditions. Seborrheic dermatitis may occur more frequently in people who have Parkinson's disease and certain other neurological disorders.
  • Stress and fatigue. Stressful life events and situations may help trigger an episode or make it worse through mechanisms that aren't yet understood. The role of neurological disorders and stress may be related through effects on the nervous system.
  • HIV/AIDS. Seborrheic dermatitis may occur more commonly and tend to be more severe in those with HIV/AIDS.
Jun. 16, 2011