Skin layer thickness, muscle elasticity and their effects on pain level in fibromyalgia patients

Fibromyalgia (FM) is a chronic, non-inflammatory syndrome characterized by widespread body pain, fatigue, sleep disturbances, impaired cognitive function and anxiety. Peripheral and central sensitization are thought to cause chronic pain in this disorder, which impairs quality of life. No specific laboratory test, radiographic method, or biomarker has been identified for diagnosis. As its physiopathology is not fully understood, no specific treatment has been identified. At this stage, studies are needed to facilitate diagnosis and guide treatment.

Eighty-nine women with FM and 36 healthy controls were enrolled in this cross-sectional, case-controlled, single-centre study. FM-related measurements (number of tender points, myalgic score, pain Visual Analogue Scale [VAS]) were recorded. All participants underwent an analysis of trapezius muscle thickness and elasticity. Skin and subcutaneous tissue thickness, and hypodermis thickness were measured by using B-mode Ultrasonography (USG) and tension (compression) Sonoelastography (SEL).

Skin thickness was lower in FM patients than in healthy controls (p < 0.01). Both trapezius muscle thickness and elastography scores were higher in the FM group compared to controls (p < 0.05 and p < 0.001, respectively). A significant correlation was found between VAS score and elastography scores (r = 0.661, p < 0.001); however, there was no significant correlation between VAS score and trapezius or skin thickness.

Patients with FM have lower skin thickness and higher trapezius muscle thickness and elastography scores than healthy controls. The thinner skin thickness in FM compared to controls may represent a potentially important factor in the pathophysiological mechanism of peripheral sensitization.