The Risks. The Causes. What You Can Do.
Basal cell carcinoma (BCC) is caused by damage and subsequent DNA changes to the basal cells in the outermost layer of skin. Exposure to ultraviolet (UV) radiation from the sun and indoor tanning is the major cause of BCCs and most skin cancers.
Understanding what causes BCC and the factors that increase your risk of getting it can help you prevent the disease or detect it in its earliest stages, when it’s easiest to treat.
These factors increase your BCC risk:
- UV exposure from the sun or indoor tanning.
- History of skin cancer, including squamous cell carcinoma (SCC) or melanoma.
- Age over 50: Most BCCs appear in people over age 50.
- Fair skin: People with fair skin have an increased risk.
- Male gender: Men are more likely to develop BCC.
- Chronic infections and skin inflammation from burns, scars and other conditions.
What causes basal
Almost all BCCs occur on parts of the body excessively exposed to the sun. Occasional extended, intense sun exposure that leads to sunburn and cumulative sun exposure over your lifetime are the main causes of skin damage that can lead to BCCs.
The more time you spend in the sun, from beach vacations to walking the dog, the greater your likelihood of developing BCC. If your occupation requires long hours outdoors or if you spend your leisure time in the sun, your risk increases even more.
It’s a fact
of nonmelanoma skin cancers (mainly BCCs and SCCs) are associated with exposure to UV radiation from the sun.
Fortunately, UV exposure is a controllable risk factor.
Tanning beds emit UV radiation that is dangerous and raises your risk of developing BCC.
- More than 419,000 cases of skin cancer in the U.S. each year are linked to indoor tanning, including about 245,000 BCCs.
- People who have ever tanned indoors have a 29 percent increased risk of developing BCC.
- Any history of indoor tanning increases your risk of developing BCC before age 40 by 69 percent.
Skin cancer history
If you’ve already had a BCC, you are at risk for developing others over the years, either in the same area or elsewhere on the body. You are also at increased risk of developing other forms of skin cancer, including squamous cell carcinoma (SCC) and melanoma.
Age over 50
As you age, you accumulate sun exposure and sun damage, raising your risk of developing BCC. In the past few decades, the number of new BCC cases has increased sharply and the average patient age has steadily decreased. Today, dermatologists report that more 20- and 30-year-olds are being treated for BCCs, a trend that experts attribute to increased outdoor UV exposure and indoor tanning.
All people with a history of sun exposure or indoor tanning can develop BCC. However, people with fair skin, blond or red hair, blue, green or grey eyes, or skin that freckles or easily burns are at highest risk.
The threat of skin cancer still exists for people with darker skin tones, and their need for sun safety is also absolutely essential. If you don’t know your skin type, take the quiz.
Men with BCC continue to outnumber women with the disease, but more women are now getting BCCs than in the past.
Skin injuries, inflammation or infection
On rare occasions, BCCs develop on areas unexposed to UV radiation. In very rare cases, exposure to other forms of radiation or certain chemicals, chronic inflammatory skin conditions and complications of burns, scars or infections can be contributing factors.
Julie K. Karen, MD
Ronald L. Moy, MD
Last reviewed: May 2019