A further therapeutic strategy is the use of crisaborole, a topical anti-inflammatory phosphodiesterase-4 (PDE4) inhibitor approved by the US Food and Drug Administration (FDA) for the treatment of atopic dermatitis [258], which is superior even to topical immunomodulators such as tacrolimus and pimecrolimus [259]. This evidence concerns the gene PDE4A and atopic eczema.