Melanoma, the most dangerous form of skin cancer, is on the rise with rates up about 7 percent in the last four years, and the condition is more prevalent among older men than women, according to data collected on millions of Americans with private health insurance.

The findings come from the Blue Cross Blue Shield Health Index, which gathers medical claims data from 41 million insured members up to age 64.  Independence Blue Cross, one of 36 Blue Cross plans across the country, is the Philadelphia region's largest insurer.

The Health Index analyzed claims data in 2013 and 2016, and found the number of cases of melanoma increased by 20,000.

The report does not give reasons for the increase, said Ginny Calega, a physician and vice president for medical management and policy at Independence Blue Cross.

"There are so many things you can infer from claims data," she said. "This allows us to go back and ask more questions."

Skin cancer, including far-less lethal forms than melanoma, is the most common cancer in the United States, with about 9,500 people diagnosed with some form every day, the American Academy of Dermatology reported. Melanoma accounts for about 2.8 percent of all skin cancer diagnoses.

The Blues report ranked states and metropolitan areas by prevalence rates of all forms of skin cancer.

For 2016, the national average was 4.3 percent, lower than the Philadelphia region's 5.8 percent.

Sarasota-Bradenton, on Florida's west coast, had the nation's highest rate, at 10 percent followed closely by Fort Pierce-Port St. Lucie and West Palm Beach-Boca Raton, all on the state's east coast, which each had a rate of 9.5 percent.

There were interesting variations in the data.

Sunny Texas cities such as Laredo (1.1 percent) and El Paso (1.4 percent) came in well below cloudy Syracuse, N.Y., at 6.2 percent. And Hawaii, which has more than 3,000 hours of sunshine every year, had a diagnosis rate of just 1.8 percent.

It would be speculation to say why these variations occur, said Calega, but the disparities give the insurer an opportunity to look more closely to see if education efforts need to be ramped up in some areas.

Calega said Blue Cross covers visits with clinicians who can provide skin checks. Either a primary care physician or dermatologist can perform an annual skin check, she said.

The report said Blue Cross pays $5.3 billion in claims each year to treat skin cancers.

"This is one [cancer] where early detection matters," said Dr. Lynn Schuchter, chief of the division of hematology and oncology at Penn Medicine's Abramson Cancer Center, about melanoma. "If it does occur, most patients are cured by surgery."

Melanoma has been on the rise in the general population, she said.

"In general, there are 91,000 cases of invasive melanoma in the United States," Schuchter said. That number continues to climb every year.

Women tend to get skin cancer on their extremities and fare better in treatment than men, who tend to develop the cancer on their trunk, Schuchter said. There is a lot of melanoma in men over 64 years old, she said.

Among young patients, particularly women, the most alarming trend has been melanoma developing in those using tanning beds, with their high levels of harmful ultraviolet rays, Schuchter said. According to the Skin Cancer Foundation, using a tanning bed before age 35 makes the risk of melanoma jump by an average of 75 percent.

Experts recommend self-checks monthly, following the ABCDE rule.

  • A for asymmetry. Look for any mismatched sides of moles.

  • B for border. Check for any irregularities or jagged edges.

  • C for color. Moles with inconsistent coloring or those that are discolored are cause for concern.

  • D for Diameter. Moles larger than about a quarter-inch should be checked.

  • E for evolving. Any changes in size or shape are a warning sign.

There are some things you can do to protect your skin.

  • Use sunscreen labeled "broad spectrum" with SPF of over 30 before going outside. Reapply at least every two hours.

  • Limit time in the sun and avoid tanning beds. Spray tans will bronze you without harmful UV exposure.

  • Wear wide-brimmed hats and sunglasses to block UV rays.