Clinical Characteristics Associated with Musculoskeletal Extracutaneous Manifestations in Pediatric and Adult Morphea: A Prospective, Cohort Study.

Morphea is an autoimmune condition of the skin associated with functional sequelae resulting from musculoskeletal involvement. Systematic investigation of risk for musculoskeletal involvement is limited, particularly in adults. This knowledge gap impairs patient care because practitioners are unable to risk stratify patients. To address this gap, we determined the frequency, distribution, and type of musculoskeletal (MSK) extracutaneous manifestations affecting joint and bone with overlying morphea lesions using cross-sectional analysis of 1,058 participants enrolled in two prospective cohort registries (Morphea in Children and Adults Cohort [n = 750] and National Registry for Childhood Onset Scleroderma [n = 308]). Additional analysis included the identification of clinical features associated with MSK extracutaneous manifestations. MSK extracutaneous manifestations occurred in 274 of 1,058 participants (26% overall, 32% pediatric, and 21% adults). Children had a limited range of motion of larger joints (i.e., knees/hips/shoulders), whereas the involvement of smaller joints (i.e., toes/temporomandibular joint) was more common in adults. Multivariable logistic regression showed that deep tissue involvement had the strongest association with musculoskeletal features, with a lack of deep tissue involvement having a negative predictive value of 90% for MSK extracutaneous manifestations. Our results underscore the need to evaluate MSK involvement in adult and pediatric patients and the utility of using depth of involvement in addition to anatomic distribution to risk stratify patients.