Axonal hyperexcitability after combined NGF sensitization and UV-B inflammation in humans.

Background: Both nerve growth factor (NGF) and ultraviolet-B (UV-B) irradiation sensitize nociceptive nerve endings and increase axonal excitability of nociceptors. Combining NGF and UV-B treatment is supra-additive for sensory sensitization and even caused spontaneous pain in about 70% of the subjects.

Methods: UV-B irradiation was performed at day 21 after intradermal NGF injection in 13 volunteers.