Rapid peripheral reprogramming of myelinated afferents drives human hyperalgesia.

A small burn can render a large area of skin painfully tender. This widespread hyperalgesia protects injured tissue and is typically attributed to altered spinal cord mechanisms. Whether peripheral sensory afferents directly interact to contribute to hyperalgesia remains unclear. Using single-unit microneurography, we recorded cutaneous afferents before and after inducing localized TRPV1-mediated inflammatory flare. This triggered minutes-scale reweighting of transcriptomically defined TRPV1- afferents, with divergent effects among myelinated (Aβ-range) classes: tactile receptors showed reduced responsiveness, whereas mechano-nociceptors underwent sensitization. These changes paralleled diminished tactile sensitivity and intensified mechanical pain. Recruitment of mechanically silent branches in Aβ-range mechano-nociceptors produced wide-field amplification of peripheral nociceptive signaling beyond the inflamed site. These findings suggest that rapid peripheral crosstalk from TRPV1+ afferents reprograms TRPV1- Aβ-afferents and drives human hyperalgesia.