Skin cancers are the most common cancers diagnosed in North America, according to the National Cancer Institute, and while everyone is at risk, people with some chronic illnesses may need to be extra vigilant about sun protection.

Some past research found that people living with inflammatory bowel disease (IBD) who were taking thiopurines — immunosuppressive medications such as azathioprine or mercaptopurine — were at an increased risk of developing nonmelanoma skin cancers (NMSC) and melanoma, which is less common and more life-threatening.

But a systematic review published May 2020 in the journal JAMA Dermatology found no significant link between immunotherapy treatment and an increased risk for skin cancer in patients with inflammatory conditions such as IBD, psoriasis, and rheumatoid arthritis. Contrary to past research, which suggested that suppressing the immune system would make the body more vulnerable to getting skin cancer, the 2020 study didn’t find any statistically significant links between the two.

According to Michelle A. Weir, MD, an assistant professor of clinical dermatology at Penn Medicine in Philadelphia, it’s important to distinguish between melanoma and nonmelanoma skin cancers when considering skin cancer risk for people with IBD.

“Many immunosuppressive therapies that are commonly used to treat patients with Crohn’s disease have been shown to increase the risk for nonmelanoma skin cancers, which include basal cell carcinoma and squamous cell carcinoma,” says Dr. Weir. “This risk increases when you consider non-IBD factors such as older age, amount and intensity of UV exposure over one’s lifetime, and skin type.”

The new study looked only at patients’ risk of melanoma.

While patients with Crohn’s may have an increased risk for certain types of skin cancer, whether that increased risk is due solely to IBD or to immunosuppressive therapy is difficult to distinguish, notes Weir.

Ioannis Economou, MD, a gastroenterologist at Rush Center for Crohn's and Colitis in Chicago, Illinois, says there is evidence of melanomas occurring in areas of the body that have been repeatedly sunburnt. Some researchers believe this could be due to a faulty immune system that fails to pick up and target cancerous tumors, or that increased inflammation in the body can make the skin more susceptible to sun exposure.

Others have suggested the higher incidence of skin cancers in people with IBD may be related to the fact that they visit healthcare facilities more often than the general population, so there's a greater chance skin cancer will be detected. Until more studies with larger patient groups are conducted, notes the 2020 study, we won’t know for sure whether biologic therapies for common inflammatory diseases like Crohn’s can affect your risk of developing skin cancer.

“We tell our patients who are on immunosuppressant medications that they need to be extra careful about sun protection, and see a dermatologist more frequently,” says Ed Loftus Jr., MD, a gastroenterologist at Mayo Clinic in Rochester, Minnesota.

Doctors and researchers agree that the risks of not taking IBD medication usually outweigh the risks of developing skin cancer. They recommend patients go for regular screenings at a dermatologist, as well as take sun protection measures.

“Controlling inflammation within the body is incredibly important in maintaining the overall health of a patient with IBD because it decreases their risk for complications, infections, and other types of cancers,” says Weir. “Skin cancer surveillance with annual skin checks is recommended for all patients on immunosuppressive therapy. Regular visits to a dermatologist can result in early detection of skin cancers, which can typically be managed with straightforward interventions.”

Other factors that may put you at increased risk of skin cancer are:

Fair skin
A tendency toward atypical moles
Age
A history of painful or bad sunburns
An outdoor work environment
A family history of skin cancer

How to Protect Yourself From the Sun

A study published in the Journal of Skin Cancer in February 2016 found that although people with IBD tend to be well-informed about skin cancer and aware of worrying skin characteristics, they don’t always use proper skin protection and prevention measures. The study, which found that people over age 40 scored higher on prevention knowledge, and that women scored higher on skin protection than men, encourages health professionals to reinforce skin cancer prevention among patients with IBD.

Here are some simple steps you can take to lower your risk of skin cancer:

Avoid direct sunlight, especially between 10 a.m. and 4 p.m.
Use sunscreen (SPF 30 or higher), even when it’s overcast.
Don’t tan or use tanning booths.
Wear protective clothing and a wide-brimmed hat in sunlight.
Examine your skin often to check for suspicious-looking moles, lesions, or scaly patches of skin.
Have yearly skin screening examinations, or more frequent ones, depending on your dermatologist’s advice.

Additional reporting by Kaitlin Sullivan.