One of the best measures we have for determining who will develop skin cancer is counting how many moles a person has on her body. Having more than 50 moles means you're at an increased risk for melanoma, the most serious type of skin cancer, according to the Mayo Clinic.
But counting moles can be time consuming -- and few doctors do a full-body mole count during yearly checkups, according to research published in the journal Clinical Dermatology in 2013. Now, a new study of nearly 4,000 pairs of female twins has developed a workaround for physicians: counting the number of moles on a patient's right arm.
According to the study, published in the British Journal of Dermatology in September, the number of moles on a patients right arm is a reliable predictor for the number of moles on a patients whole body. If a patient has 11 or more moles on her right arm, she's 9 times more likely to have 100 moles on her whole body, which significantly ups her risk of melanoma.
What counts as a mole?
But what exactly counts as a mole? But before you drive yourself crazy trying to differentiate between your moles and freckles, we asked lead study author Simone Ribero of the department of twin research and genetic epidemiology at King’s College, to help explain the difference between the two.
"Moles do not change with sun exposure, while freckles do," Ribero told HuffPost. Most moles are brown or black and occur during the first 20 years of life, according to the Cleveland Clinic. While most moles are benign, dermatologists recommend monitoring them for changes in size, color and shape. If you notice any changes, head to a dermatologist to get checked out.
And while freckles don't have any direct health implications, people who freckle easily are at an increased risk for skin cancer, and should take extra care to avoid sun exposure and use sunscreen.