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The prevalence of neuropathic-like pain was found to be high in patients with psoriatic arthritis (PsA), a condition that may be associated with higher disease activity and fibromyalgia, according to study results published in Clinical Rheumatology.

Central sensitization has been observed in rheumatic diseases, including rheumatoid arthritis. The goal of the current study was to assess the prevalence of neuropathic-like pain in patients with PsA, using the PainDetect Questionnaire. Secondary outcome measures included disease activity assessment, brief inventory score, tender and swollen joint count, examination for dactylitis and enthesitis, American College of Rheumatology 2010 fibromyalgia questionnaire score, hospital anxiety and depression scale, fatigue severity score, and fatigue impact scale.

The study cohort included 64 adult patients with a clinical diagnosis of PsA who visited a rheumatology outpatient department. As indicated by scores on the PainDetect questionnaire, 17 patients (26.6%) were classified as having “likely neuropathic pain,” 14 patients (21.9%) as having “possible neuropathic pain,” and 33 patients (51.6%) as having “unlikely neuropathic pain.”

Disease activity was found to be higher in patients with “likely neuropathic pain” compared with those with “unlikely neuropathic pain,” as indicated by tender and swollen joint counts, pain scores, patient global assessment, and dactylitis and enthesitis scores. Patients with likely or possible neuropathic pain were found to have greater pain interference and effect and higher levels of fatigue, anxiety, and depression compared with participants with unlikely neuropathic pain. The PainDetect scores correlated positively with measures of disease activity and associated symptoms and score on the Widespread Pain Index and Symptom Severity Scale.

The Polysymptomatic Distress Scale scores indicated a greater degree of “fibromyalgianess” in participants in the likely vs unlikely neuropathic pain group. “Our interpretation is that ‘fibromyalgianess’ in PsA is a continuum and represents abnormal pain processing in patients experiencing chronic nociceptive pain,” noted the study authors.

Study limitations include the inclusion of patients with fibromyalgia, a population in which the PainDetect tool has been shown to not be useful for assessing neuropathic pain; the inclusion of patients with type 2 diabetes with possible diabetic neuropathy; the lack of a control group; and a small sample size.

“PsA patients are severely affected by a variety of symptoms beyond pain and disease activity, which have detrimental biopsychosocial effects. This indicates that their care must be tailored to address all of these problems experienced to achieve the most effective management and therefore best possible quality of life,” concluded the researchers.