Performance of ultra-high-frequency ultrasound in the evaluation of skin atrophy in patients with long-term oral glucocorticoid therapy in a tertiary rheumatology center.

Ultra-high-frequency ultrasound (UHF-US) allows visualization of the epidermis, dermis, and subcutis and precise measurement of skin thickness. The aim of this study was to assess the performance and interobserver reliability of UHF-US for measuring skin thickness in patients with long-term systemic glucocorticoid (GC) therapy compared to patients without GC therapy or treated for a shorter period.156 patients with known or suspected inflammatory rheumatic diseases underwent US evaluation for skin thickness by 3 experts in 3 anatomical sites (hand, distal, and proximal forearm). 87 patients were classified as "frequent users" who had received continuous oral GCs for at least one year or at least 3 years with various interruptions. 69 patients without any oral GC therapy in the past or treated for a shorter period were classified as "non-frequent users".UHF-US allowed a precise measurement of skin thickness. Skin thickness at all 3 anatomical sites was significantly decreased in "frequent users" of GCs compared to "non-frequent users" (distal and proximal forearm: p < 0.001; hand: p < 0.05). At all 3 anatomical sites, skin thickness was decreased in patients with clinically assessed parchment-like skin compared to patients without parchment-like skin (distal and proximal forearm: p < 0.001; hand: p < 0.05). Interobserver variability was excellent [hand intraclass correlation coefficient (ICC) = 0.99; proximal forearm ICC = 0.85; distal forearm ICC = 0.84].These data support the idea of UHF-US as an objective and reliable imaging tool for monitoring skin atrophy as adverse effects of GC therapy.