Background Skin thickness in systemic sclerosis (SSc) may be measured by high frequency ultrasound. Most studies have a cross sectional design.
Objectives The aim of the study was to study the changes in high frequency ultrasound of the skin during one year of follow-up in SSc.
Methods In this retrospective study we identified 113 patients in whom ultrasound examination was performed at baseline and at the one year follow-up at 5 predefined sites. 37 were classified as diffuse cutaneous SSc (dcSSc) and 76 as limited cutaneous SSc (lcSSc).
Results There were significant changes in skin thickness of the chest (p=0.002) and in the total sum of skin thickness (p=0.008) during the observation time. The changes of skin thickness of the phalanx, back of hand, forearm and lower leg were however not significant.
There was an inverse correlation between total skin thickness and disease duration (rS: -0.26; p=0.005).
Anti RNA polymerase III (ARA) positive patients displayed significantly larger variance in change of total skin thickness than patients with centromeric antibodies (ACA) (p=0.003), anti topoisomerase I antibodies (ATA) (p=0.017), and ANA without ACA, ATA or ARA (p=0.045).
Paired T-test showed that total skin thickness was reduced in the 18 patients treated by Cyclophosphamide (p=0.015) whereas no reduction of total skin thickness was seen after treatment with Azathioprine, Methotrexate or Mycophenylatemofetil.
45 patients treated with Prednisolone showed a reduced total skin thickness (p=0.015) whereas there was no difference in patients not treated with Prednisolone.
The ultrasound measurements of skin thickness correlated to serum-cartilage oligomeric matrix protein (serum-COMP) (rS: 0.38; p=0.001) and the modified Rodnan skin score (mRSS) (rS: 0.51; p=0.001) at baseline and the 1-year follow-up (rS: 0.47; p<0.001 and rS: 0.51; p<0.001 respectively). At 1-year follow-up total skin thickness also correlated to hand mobility in scleroderma (HAMIS) values (rS: 0.47; p<0.001).
Changes in total skin thickness correlated with changes in mRSS (rS: 0.32; p=0.001) and HAMIS (rS: 0.36; p=0.004) during the same time period.
Conclusions In SSc, measurement of skin thickness by high frequency ultrasound, enables us to better understand the complex process of skin fibrosis in regard to the evolvement of oedema and skin contractions and the diversity between phenotypes and effects of therapies.
Disclosure of Interest None declared