title: The sunburn pain model: the stability of primary and secondary hyperalgesia over 10 hours in a crossover setting.
abstract: It was our aim to study the within-day stability and between-day repeatability of ultraviolet B (UVB) light-induced primary and secondary hyperalgesia over 10 h. Twenty hours after UVB irradiation of a skin spot (r = 2.5 cm) on the upper leg of 8 healthy volunteers the areas of secondary hyperalgesia to pinprick and pain tolerance thresholds to heat (HPTT) and electrical stimuli (5 and 250 Hz, electrical pain tolerance thresholds [EPTT]) were assessed. Measurements were repeated for 10 h at 2-h intervals and in 2 different sessions. Large areas of secondary hyperalgesia to pin prick were observed (5995 mm(2); SD, 1645). Primary hyperalgesia was evidenced by significant decreases of HPTT (mean difference, 6.5 degrees C; 95% confidence interval, 6.1-6.8; P < 0.001) and EPTT at 250 Hz (mean difference, 0.45 mA; 95% confidence interval, 0.13-0.78; P < 0.05) compared to normal skin. There was no trend within one session of either primary (P = 0.14 for HPTT) or secondary hyperalgesia (P = 0.95) and no difference between the two sessions (primary hyperalgesia, P = 0.28; secondary hyperalgesia, P = 0.07). The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia.
  
  
  CONCLUSIONS
  The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia.
authors.affiliation: From the Department of Anesthesia and General Intensive Care Medicine (B), University of Vienna, Vienna, Austria.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Gustorff
authors.forename: Sebastian
authors.initials: S
authors.lastname: Anzenhofer
authors.forename: Thomas
authors.initials: T
authors.lastname: Sycha
authors.forename: Stephan
authors.initials: S
authors.lastname: Lehr
authors.forename: Hans G
authors.initials: HG
authors.lastname: Kress
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology*; D010146:Pain / Q000209:etiology*; D017288:Pain Threshold / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply / Q000473:pathology; D013471:Sunburn / Q000150:complications* / Q000473:pathology; D014466:Ultraviolet Rays