BP risk factors include age, specific systemic medications, UV radiation, and infections.2, 3, 4, 5 Medications associated with drug-induced BP include antibiotics, angiotensin converting enzyme inhibitors, dipeptidyl peptidase 4 inhibitors, non-steroidal anti-inflammatory drugs, salicylates, diuretics, immune checkpoint inhibitors such as programmed cell death protein 1 and programmed cell death-ligand 1 inhibitors, and others.2 This evidence concerns the gene PDCD1 and infection.