TACR1 and erythema multiforme: In this study, we focused on peripheral sensitization of EM-associated nerve fibers: we investigated (i) the nerve fiber density of sensory nerve fibers in symptomatic EM patients, (ii) analyzed the expression of the SP and their receptor NK1R and (iii) the expression of nociceptive receptors and compared the findings between EM patients and controls and between patients using or not using hormonal treatment.