Topical corticosteroids, such as hydrocortisone, have proven effective in managing AD. If topical corticosteroids and moisturisers fail, short-term treatment with topical calcineurin inhibitors like tacrolimus or pimecrolimus may be tried, although their use is controversial as some studies indicate that they increase the risk of developing skin cancer or lymphoma. A 2007 meta-analysis showed that topical pimecrolimus is not as effective as corticosteroids and tacrolimus. However a 2015 meta-analysis indicated that topical tacrolimus and pimecrolimus are more effective than low dose topical corticosteroids, and found no evidence for increased risk of malignancy or skin atrophy. In 2016, crisaborole, an inhibitor of PDE-4, was approved as a topical treatment for mild-to-moderate eczema.