JAK inhibitors for the treatment of juvenile localized scleroderma: a case report and literature review

Juvenile localized scleroderma (JLS) is a chronic autoimmune and fibrosing disease that can cause significant damage and impairments. Currently, management of JLS is challenging due to the paucity of antifibrotic drugs. In patients with severe JLS, systemic glucocorticoids(GCs) combined with methotrexate(MTX) are recommended, but some patients show intolerance or poor response. Janus kinase (JAK) inhibitors have demonstrated efficacy and tolerability in treating cutaneous thickening in vivo and in vitro. We aim to describe a JLS patient treated with upadacitinib(UPA) in our hospital and to present a focused review of the literature on the use of a JAK inhibitor for the treatment of localized scleroderma. We describe a boy who experienced mild pain in his right finger joints, red lesions and skin induration on his right hand that gradually spread to his upper arm, resulting in joint contractures. A skin biopsy revealed increased collagen deposition and moderate inflammation. He was diagnosed with linear scleroderma. After treatment of MTX, prednisone, and tocilizumab, he had only partially reduced skin disease activity and failed to halt the progressive worsening of his joint mobility. His course was complicated by bilateral suppurative granulomatous lymphadenitis. After switching to UPA in combination with MTX at 43 months after disease onset, he experienced significant clinical improvement within three months, including reduced skin lesion activity, improved joint mobility, and resolution of right-hand ulnar numbness. At the six-month, he showed ongoing improvement in his skin condition and complete resolution of anxiety. The only adverse effect he experienced was mild MTX-related nausea. UPA emerges as an alternative drug for JLS patients displaying resistance or partial responsiveness to other drugs, particularly for those with skin and/or articular involvement. JAK inhibitors demonstrate notable efficacy and good tolerance in the majority of patients with localized scleroderma.