A comparative study of clinical signs in fibromyalgia/fibrositis syndrome, healthy and exercising subjects. 
Pain threshold to pressure, skinfold tenderness, reactive skin hyperemia and tissue compliance were assessed in 60 subjects with fibromyalgia (FS) and 60 pain free [total control, (TC)] subjects comprising 30 normal controls (NC) and 30 exercising fit (FC) subjects.  Pain threshold was significantly lower in FS than in TC (p = < 0.001) and NC (P = < 0.001).  Skinfold tenderness was present in 95% of FS and 33% of the NC but was absent in all FC.  In patients this tenderness was present both in painful and nonpainful sites, and when positive was significantly (P = < 0.001) more painful than in controls.  Reactive skin hyperemia to pressure was significantly (p = < 0.001) increased in patients with FS compared to TC, but not to NC.  Tissue compliance at trapezius, thoracic and lumbar locations was significantly (p = < 0.001) lower in patients than in any other controls.  The fit subjects significantly differed from the unfit for pain threshold (p = < 0.001), reactive skin hyperemia (p = < 0.001), tissue compliance at right trapezius (p = < 0.001) and right thoracic (p = < 0.001) levels, and for the skinfold test (p = < 0.01).  These 4 clinical signs could differentiate patients from controls with a mean accuracy of 86%.  Our study indicates that there are clinical signs, apart from the tender points, which are abnormal in FS that appear to be useful as objective signs in the assessment of patients with FS, whether for diagnostic, therapeutic or research purposes.