I have 1 basal cell carcinoma which gets surgery this month.
However I am of the age where as teenagers we sat out in the sun, I never did use the mixture of baby oil & iodine to get a tan though, we were outside all the time in the summer sun without hats & wearing shorts & had never heard of sunscreen then other than Coppertone, we had sun lamps, . I'd bet that's where mine came from, damage caused while growing up. I was on prednisone for almost 4 years w/ITP - can't recall if I was told to stay out of the sun while taking it. Know I've taken some antibiotics that say limit time in the sun while taking. So who knows why, could be any number of things I guess.
Sorry you are having to deal with this, it's good you see the dermatologist every year so it was caught early.
Good luck!!
"Instead of wasting your time worrying about symptoms, just get it checked out" -Nieca Goldberg, MD
