Operated by Aclaris Therapeutics


“Why did I get these?”

Though seborrheic keratosis (SK) is an extremely common skin growth, surprisingly little is known about the actual cause(s).  Here are the common theories*:

  • Genetics: In many cases, the condition seems to run in families, particularly for people with a large number of SKs.  Researchers have recently found two gene mutations that may play a role in the development of SK in a significant percentage of patients. The occurrence of these gene mutations (and potentially others) increases with age, which may be one of the reasons why SKs tend to appear as we get older.
  • Sunlight: Sunlight has not been definitively proven to play a role in the development of SKs.  Some people have most of their SKs in sun-exposed areas, such as the face and neck, but others have SKs in well-covered areas, such as the crease beneath the breasts. One Australian study found that sunlight contributed to the development of SKs in people prone to getting them, but a Dutch study found no connection between lifetime sun exposure and SKs.Ɨ  As the debate continues among the experts, you probably don’t need to blame yourself for your SKs if you were less than diligent about using sunscreen in your youth–but you should still be sure to use your sunblock!
  • Viruses: Because SKs sometimes look like warts, a theory has been proposed that perhaps they may be related to or caused by the human papillomavirus (HPV), the same virus responsible for warts on the body.  While some researchers found the virus in nearly 20% of the SKs they studied, all that they could conclude was that the virus was present in the SK, but not that it actually caused the SKs.

So, because the cause of SKs is not known, there is no really good advice about how to prevent them. Researchers continue to search for the cause of SKs with the hope of a discovery that could lead to a cure or preventive treatment.  In the meantime, if your SKs are a concern to you, see your dermatologist about treatment.

*Jackson JM, Alexis A, Berman B, Berson D, Taylor S, Weiss J. Current Understanding of Seborrheic Keratosis:  Prevalence, Etiology, Clinical Presentation, Diagnosis, and Management.  J Drugs Dermatol  2015;14(10):1119-1125.

ƗKennedy C, Bajdik C, Willemze R, de Gruijl FR, Bouwes Bavinck JN, for the members of the Leiden Skin Cancer Study. The Influence of Painful Sunburns and Lifetime Sun Exposure on the Risk of Actinic Keratoses, Seborrheic Warts, Melanocytic Nevi, Atypical Nevi, and Skin Cancer. J Invest Dermatol 2003;120:1087-1093.