Significant Muscle Hemorrhage Associated With Low-Molecular-Weight Heparin Use in Dermatomyositis: A Case Report

Dermatomyositis is a rare systemic inflammatory disease with characteristic skin features and muscular involvement. Few cases of hemorrhagic myositis with dermatomyositis have been reported worldwide. Here, we report a case of a 43-year-old man with dermatomyositis, which was treated with steroids and low-molecular-weight heparin. During the treatment course, he complained of acute left thigh pain. Computed tomography of the lower extremity showed hemorrhage in the left iliopsoas, iliacus, thigh muscle, and retroperitoneum. We discontinued heparin treatment and applied a splint with bed rest. Ultimately, he had a successful recovery. Patients with dermatomyositis may have an intrinsic risk of life-threatening muscle hemorrhage, and anticoagulation treatment may induce significant muscle hemorrhage in such patients.