Itch sensitization? A systematic review of studies using quantitative sensory testing in patients with chronic itch

Antoinette I.M. Van Laarhoven, Jens B. Marker, Jesper Elberling, Gil Yosipovitch, Lars Arendt-Nielsen, Hjalte H. Andersen

Research output: Contribution to journalReview article

3 Scopus citations

Abstract

As well established for patients with chronic pain, patients suffering from chronic itch also exhibit signs of peripheral and central sensitization. This has been linked to parallel neuroplastic sensitization processes. However, for chronic itch, sensitization has not yet been systematically assessed, studied, and hence validated. This review (Prospero CRD42016043002) summarizes and meta-analytically evaluates whether sensory aberrations including sensitization for itch occur in chronic itch. Databases PubMed, Embase, and Cochrane Library were searched for studies investigating somatosensory sensitivity assessment by quantitative sensory testing stimuli, including experimental cutaneous chemical pruritic provocations, in patients with chronic itch from skin/neurological conditions and compared with healthy controls. Outcomes were extracted for lesional and nonlesional skin, and risk of biases were assessed. Meta-analyses were performed when sufficient quantitative data were available. Of 4667 identified articles, 46 were included and 25 were eligible for meta-analyses. Patients (66% atopic dermatitis [AD]) were found more sensitive than the controls to histamine-evoked itch in lesional skin (standardized mean difference [SMD]: 0.66 confidence interval [CI]: 0.16-1.15), but not nonlesionally (SMD: -0.26 [CI: -0.58 to 0.06]). Cowhage did not evoke more itch in nonlesional skin of patients as compared to the controls (SMD: 0.38 [CI: -0.04 to 0.81]). For numerous other chemical provocations as well as for mechanical, thermal, and electrical stimulation paradigms, results were ambiguous or based on few studies. Patients with chronic itch are only robustly sensitized to various chemical pruritic stimuli when applied lesionally. More studies on somatosensory aberrations in chronic itch conditions other than AD are needed to establish whether sensitization is robustly present across chronic itch conditions.

Original languageEnglish (US)
Pages (from-to)2661-2678
Number of pages18
JournalPain
Volume160
Issue number12
DOIs
StatePublished - Dec 1 2019

Keywords

  • Alloknesis
  • Central sensitization
  • Hyperknesis
  • Neuroplasticity
  • Pain
  • Peripheral sensitization
  • Pruritus
  • Quantitative sensory testing

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Anesthesiology and Pain Medicine

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  • Cite this

    Van Laarhoven, A. I. M., Marker, J. B., Elberling, J., Yosipovitch, G., Arendt-Nielsen, L., & Andersen, H. H. (2019). Itch sensitization? A systematic review of studies using quantitative sensory testing in patients with chronic itch. Pain, 160(12), 2661-2678. https://doi.org/10.1097/j.pain.0000000000001678