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Association between pain, central sensitization and anxiety in postherpetic neuralgia
Author(s) -
Schlereth T.,
Heiland A.,
Breimhorst M.,
Féchir M.,
Kern U.,
Magerl W.,
Birklein F.
Publication year - 2015
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.537
Subject(s) - allodynia , medicine , postherpetic neuralgia , hyperalgesia , sensitization , anesthesia , threshold of pain , neuropathic pain , nociception , anxiety , psychiatry , receptor , immunology
Abstract Background In postherpetic neuralgia ( PHN ), dorsal root ganglia neurons are damaged. According to the proposed models, PHN pain might be associated with nociceptive deafferentation, and peripheral (heat hyperalgesia) or central sensitization (allodynia). Methods In 36 PHN patients, afferent nerve fibre function was characterized using quantitative sensory testing and histamine‐induced flare analysis. Psychological factors were evaluated with the Hospital Anxiety and Depression Scale ( HADS ), disease‐related quality of life ( Q oL) with SF ‐36 and pain with the M c G ill questionnaire [pain rating index ( PRI )]. The patients were also divided into subgroups according to the presence or absence of brush‐evoked allodynia as a sign of central sensitization. Results For all patients, warm, cold and mechanical detection was impaired ( p < 0.001 each) and the size of the histamine flare was diminished on the affected side ( p < 0.05); pain thresholds with the exception of brush‐evoked allodynia ( p < 0.05) were unaltered. Correlation analysis revealed allodynia, anxiety, depression, Q oL and age as relevant factors associated with pain severity ( PRI ). Allodynia was present in 23 patients (64%). In these patients, heat pain perception was preserved; the histamine flare was larger; the pinprick pain was increased as were M c G ill PRI sensory subscore, actual pain rating and almost significantly pain ( M c G ill PRI ) over the last 4 weeks. Conclusions PHN is associated with damage of afferent fibres. Central sensitization (i.e., allodynia) might contribute to PHN pain. There was a striking association between anxiety, depression and age, and the magnitude of PHN pain.