Seborrheic Dermatitis
Overview:
Seborrheic dermatitis is a very common skin condition primarily affecting the scalp and face that many people know as cradle cap or dandruff. It can result is red, itching, and flaking skin most commonly on the scalp and face.
Epidemiology:
Seborrheic dermatitis is common in the first year of life as cradle cap. Its incidence then returns in adolescence and adulthood. Seborrheic dermatitis can be more severe and more common in patients with Parkinson’s Disease and HIV.
Pathogenesis:
The exact cause is unknown but it is theorized to be inflammation as a result of an immune response to Malassezia yeast on the skin. While it is not a disorder of the sebaceous gland, increased sebaceous oil secretion can contribute perhaps by providing a favorable environment for the yeast. The locations affected by seborrheic dermatitis tend to have a higher proportion of sebaceous glands such as face, scalp, upper trunk, and anogenital area.
Treatment:
Seborrheic dermatitis is an example of a skin condition that cannot be cured but can be managed and controlled. Ultimately, it is important to remember that it does not pose a threat to you overall well being. Treatment is targeted at two areas:
#1 Treatment of acute flares- Topical Steroids (solution for scalp, cream for face and body) can be applied twice daily for 2-3 weeks to resolve acute flares marked by active scale, redness, and itch. Steroids should not continue to be applied beyond 2-3 weeks as this would lead us to question the reason for treatment failure and could lead to thinning skin and stretch marks.
#2 Prevention and maintenance- Dandruff shampoos are largely targeted towards controlling the population of yeast and therefore preventing the inflammatory response. Commonly used prescription shampoos include ketoconazole and ciclopirox shampoo. There are many other over the counter shampoos which can be helpful in this condition as well. Here is a resource dedicated to helping patients select and compare the various OTC dandruff options https://www.dandruffdeconstructed.com/search/
For more information see the following:
https://www.dermnetnz.org/topics/seborrhoeic-dermatitis/
https://www.aad.org/public/diseases/scaly-skin/seborrheic-dermatitis
Seborrheic dermatitis in scalp, photo from Dermnetnz.org
Seborrheic dermatitis on face, photo from Dermnetnz.org