Subclinical dermal involvement is detectable by high frequency ultrasound even in patients with limited cutaneous systemic sclerosis.
The aim of the study was to detect by skin high-frequency ultrasound (US) possible subclinical skin involvement in patients affected by limited cutaneous systemic sclerosis (lcSSc), in those skin areas apparently not affected by the disease on the basis of a normal modified Rodnan skin score (mRSS). Differences in dermal thickness (DT) in comparison with healthy subjects were investigated.



Fifty patients with lcSSc (age 62 ± 13 years (mean ± SD), disease duration 5 ± 5 years) and 50 sex-matched and age-matched healthy subjects (age 62 ± 11 years) were enrolled. DT was evaluated by both mRSS and US at the usual 17 skin areas (zygoma, fingers, dorsum of the hands, forearms, upper arms, chest, abdomen, thighs, lower legs and feet). Non-parametric tests were used for the statistical analysis.



Subclinical dermal involvement was detected by US even in the skin areas in patients with lcSSc, who had a normal local mRSS. In addition, statistically significantly higher mean DT was found in almost all skin areas, when compared to healthy subjects (p < 0.0001 for all areas). In particular, DT was significantly greater in patients with lcSSc than in healthy subjects in four out of six skin areas with a normal mRSS (score = 0) (upper arm, chest and abdomen), despite the clinical classification of lcSSc.



This study strongly suggests that subclinical dermal involvement may be detectable by US even in skin areas with a normal mRSS in patients classified as having lcSSc. This should be taken into account during SSc subset classification in clinical studies/trials.
Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, n° 6, AOU IRCCS San Martino, 16132, Genova, Italy.
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Sulli
Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, n° 6, AOU IRCCS San Martino, 16132, Genova, Italy.
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Ruaro
Department of Rheumatology, Ghent University Hospital, Department of Internal Medicine, Ghent University, Ghent, Belgium.
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Smith
Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, n° 6, AOU IRCCS San Martino, 16132, Genova, Italy.
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Paolino
Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, n° 6, AOU IRCCS San Martino, 16132, Genova, Italy.
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Pizzorni
Laboratory of Autoimmunity, Department of Internal Medicine, University of Genova, IRCCS A.O.U, San Martino, Genoa, Italy.
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Pesce
Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, n° 6, AOU IRCCS San Martino, 16132, Genova, Italy. mcutolo@unige.it.
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Cutolo
D000005:Abdomen / Q000000981:diagnostic imaging; D000368:Aged; D001132:Arm / Q000000981:diagnostic imaging; D005260:Female; D005385:Fingers / Q000000981:diagnostic imaging; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D045745:Scleroderma, Limited / Q000000981:diagnostic imaging*; D012595:Scleroderma, Systemic / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D012867:Skin / Q000000981:diagnostic imaging* / Q000473:pathology; D013909:Thorax / Q000000981:diagnostic imaging; D014463:Ultrasonography / Q000379:methods*
Dermal thickness; High-frequency ultrasound; Nailfold videocapillaroscopy; Rodnan skin score; Systemic sclerosis