Can dermatologist tell an employee to tone down the tanning?

Q. We're a dermatology practice with 47 employees. One of our newer employees is very excessive with tanning. She comes to work with a dark tan and sometimes sun burned. We promote the opposite of what she does. We promote skin cancer awareness along with being safe in the sun. She also wears tight low cut tops. Are we allowed to say something in regards to both of these issues? – Kim, Maryland