PTGER3 and dermatitis: We suspected that the epithelium played a role in the pathobiology of CM-SJS/TEN with SOC (1) because TLR3 was strongly expressed in ocular surface epithelial cells (13, 14) and keratinocytes (20), and it regulated ocular surface inflammation (19) and dermatitis (20, 21), and because EP3, which negatively regulates mucocutaneous inflammation, was dominantly expressed on the ocular surface epithelium (24), epidermis (25), and the airway epithelium (26).