Elidel and Protopic Linked to Cancer
The FDA reports that Pimecrolimus (Elidel) and Tacrolimus (Protopic) are linked with development of skin cancers and lymphoma. Oops. As a pediatric allergist/immunologist who has prescribed both of these a fair amount this makes me a bit scared. I've also used them off label for kids <2, although apparently no cancers have been seen in this age group.
Both medicines act by inhibiting T cells and when used systemically Tacrolimus predisposes to lymphoma, so the mechanism is plausible.
Of course, both medicines, and Elidel in particular were heavily marketed as "steroid free" since parents are so steroid-phobic. I sometimes explain to parents "these medicines are powerful immunosuppressants originally designed for organ transplant recipients. Some cowboy decided to make a cream out of them and put them on the skin of kids with atopic dermatitis. Now do you feel better that you aren't using steroids, which have been used for years with minimal side effects when used correctly?"
The overall risk is quite low. According to the link, there were nearly 5 million combined prescriptions in a year and maybe 27 total malignancies over several years. Of course, this is a passive reporting system, so it underestimates risk.