UVB Irradiation as a Human Pain Model-A Scoping Review

The ultraviolet B (UVB) sunburn model is a well-established human experimental pain paradigm for investigating underlying inflammatory pain mechanisms and is used in preclinical drug development research. This scoping review aimed to provide an overview of how UVB-induced cutaneous inflammation has been applied across experimental studies, with particular emphasis on methodological characteristics, sensory outcomes, and reported safety aspects. A total of 12 studies published between 1999 and 2025, comprising 367 participants, met the inclusion criteria. Across all studies, UVB irradiation produced a clearly demarcated inflammatory response accompanied by pronounced primary hyperalgesia. Peak primary hyperalgesia was typically observed between 24 and 48 h following irradiation and remained detectable for at least 72 h. Heterogeneity was identified using UVB dose calibration strategies, spectral properties of the irradiation source, size and anatomical location of the irradiated area, timing of sensory assessment, and applied testing methodologies. In contrast to the consistent induction of primary hyperalgesia, secondary hyperalgesia was reported inconsistently and appeared to depend on methodological conditions. Post-inflammatory hyperpigmentation was reported primarily after irradiation with three minimal erythema doses, whereas lower doses appeared to provide a more favorable balance between hyperalgesia induction and tolerability. Overall, the UVB sunburn model reliably induces primary inflammatory hyperalgesia in humans. However, careful selection and standardization of methodological parameters are essential to optimize its use in mechanistic and early-phase analgesic research.