CARD14 and infection: The genetic susceptibility, variants in interleukin 36 receptor antagonist (IL36RN), adaptor related protein complex 1 subunit sigma 3 (AP1S3), and caspase recruitment domain family member 14 CARD14 genes), in additionally to environmental factors (smoking, metal allergies, female sex, autoimmune thyroid disease, stress, and infections) and dysregulation of multiple immunological pathways; in particular, the IL(interleukin)-17 and IL-36 pathways (with overexpression of IL-8) play an important role in the development of PPP [29].