Localized scleroderma (morphoea): Thickness of sclerotic plaques as measured by 15 MHz pulsed ultrasound

Abstract

The thickness of morphoea plaques was measured by A-mode ultrasound and compared to regional control measurements in the same individuals. The thickness of morphoea plaques was increased by 18-310% in 17 patients with one or a few morphoea plaques (p < 0.01), and by 13-145% in 6 patients with generalized morphoea (p < 0.05). The increase in thickness of morphoea plaques was local confined to the plaques. Ipsilateral and contralateral control measurements were not different, and measurements in a standard region (forearm) were not different from those in a group of healthy controls matched for sex and age. Plaques of clinically 'advanced' scleroderma were more thickened (p < 0.01) than plaques of 'slight' scleroderma. The relative increase in thickness was larger (p < 0.01) in skin with a habitual thickness of 0.8-1.1 mm. The habitual skin thickness on the extremities (mean 1.0 mm) was less (p < 0.01) than on the trunk (mean 1.5 mm), and, consistently, plaques with 'advanced' scleroderma were more frequent (p < 0.05) on the extremities. Ultrasound measurement of skin thickness was accurate with SD form 0.05-0.09 mm and coefficients of variation from 3-7% in reproducibility studies of typical morphoea plaques as well as normal appearing skin.