250) Association between pain and itch symptom severity after major thermal burn injury increases over time

Pain and/or itch symptoms at the tissue autograft site cause substantial morbidity after major thermal burn injury (MThBI). Increasing preclinical evidence suggests that chronic pain and chronic itch share overlapping neurobiological mechanisms (e.g., peripheral sensitization and central sensitization) and immune/glial mechanisms (e.g., activation of spinal glial cells), despite striking differences in acute pain and acute itch. However, to our knowledge, the association between pain and itch symptoms at the tissue autograft site after MThBI has not previously been assessed. We evaluated tissue autograft pain and itch severity (0-10 NRS) during the inflammatory and early proliferative phases (0-2 weeks) and late proliferative and maturation phase (3 weeks – 6 months) of wound healing among a cohort of burn survivors (n=96) who received tissue autografting within 14 days of MThBI. Associations between pain and itch symptoms on days 1, 14, week 6, and months 3 and 6 were evaluated using Pearson correlation coefficients (SPSS Statistics v23). Acute pain and acute itch are not significantly correlated in the inflammatory and early proliferative phases of wound healing (e.g., r = 0.223, p = 0.055 at 14 days post-op). However, during the proliferative and maturation phase (3 weeks – 6 months) chronic pain and chronic itch symptoms demonstrated significant and progressively increasing correlation (e.g., r=0.397, p=7.3 x 10-6 at month 3 and r=0.532, p=1.143 x 10-8 at month 6). These epidemiologic data suggest that neural, glial, and immune mechanisms mediating tissue autograft pain and itch symptoms evolve after MThBI such that they are increasingly comorbid. Further studies are needed to understand mechanisms mediating these outcomes; such studies may inform the development of improved preventive/treatment interventions. (Liu, Pflugers Arch, 2013.)