IL17A and familial pityriasis rubra pilaris: These two conditions share many molecular features such as skin barrier abnormalities (1, 4, 5), which has further led to the description of an intermediate psoriasis/familial PRP phenotype referred to as caspase recruitment domain family member 14–associated (CARD14-associated) papulosquamous eruption (4), and possibly a shared interleukin 17 (IL-17) response (6, 7).