Full Papers
Irritable bowel syndrome is related to small fibre pathology in patients with fibromyalgia
G. Paparella1, G. Paparella2, R. Barone3, M. Lupia4, E. Ammendola5, L. Clemente6, M. Delussi7, G. Lopalco8, F. Iannone9, A.M. Aloisi10, M. De Tommaso11
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro; and IRCCS Neuromed, Pozzilli, Isernia, Italy. giulia.paparella1@uniba.it
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro, Bari, Italy.
- Stress and Pain Neurophysiology Laboratory, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy.
- Stress and Pain Neurophysiology Laboratory, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy.
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro; and University Niccolò Cusano, Rome, Italy.
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro, Bari, Italy.
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro, Bari, Italy.
- Rheumatology Unit, Department of Precision and Regenerative Medicine and Ionian Area (DiMePReJ), University of Bari Aldo Moro, Bari, Italy.
- Rheumatology Unit, Department of Precision and Regenerative Medicine and Ionian Area (DiMePReJ), University of Bari Aldo Moro, Bari, Italy.
- Stress and Pain Neurophysiology Laboratory, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy.
- Neurophysiopathology Unit, Department of Translational Biomedicine and Neuroscience (DiBraiN), University of Bari Aldo Moro, Bari, Italy.
CER19936
2026 Vol.44, N°6
PI 1177, PF 1187
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PMID: 42328944 [PubMed]
Received: 20/03/2026
Accepted : 05/06/2026
In Press: 22/06/2026
Published: 22/06/2026
Abstract
OBJECTIVES:
Fibromyalgia (FM) is a multisystem disorder frequently associated with functional gastrointestinal disorders, particularly irritable bowel syndrome (IBS). Diet-related factors and gut microbiota alterations, key elements in IBS pathophysiology, may disrupt the gut-brain axis, promoting immune activation, altered pain processing, and peripheral nerve dysfunction, including small fibre involvement, which has been consistently reported in FM. The study investigated whether IBS symptom severity in FM is associated with clinical and psychological features and with neuropathological evidence of small fibre involvement.
METHODS:
In this monocentric cross-sectional observational study, 89 FM patients underwent clinical and psychological assessments. IBS severity was assessed using the IBS Severity Scoring System (IBS-SSS). Skin biopsy with quantification of intraepidermal nerve fibre density (IENFD) at proximal and distal sites was performed in 57 patients. Patients were classified into mild-moderate and severe IBS groups. Between-group differences were analysed using Mann-Whitney U and χ² tests. Spearman’s rank correlation served to assess associations between IBS severity, clinical variables, and IENFD.
RESULTS:
Severe IBS symptoms were present in 47.1% of patients. Compared with patients with mild–moderate IBS, those with severe IBS showed higher widespread pain index (WPI) and symptom severity scale (SSS) scores, indicating greater fibromyalgia severity, as well as increased anxiety and depressive symptoms, reduced sleep duration, and greater functional impairment (all p<0.05 after FDR correction). Skin biopsy revealed a higher prevalence of reduced IENFD, particularly at proximal sites, in severe IBS patients. Notably, IBS-SSS scores were negatively correlated with proximal IENFD (r=-0.34, p=0.01).
CONCLUSIONS:
IBS severity identifies a clinically more severe FM phenotype with small fibre pathology. These findings are consistent with a possible interaction between gastrointestinal dysfunction and peripheral nerve involvement in FM, although mechanistic pathways require further investigation.
