Open Access Case Report

An Atypical Presentation of Dermatomyositis Sine Dermatitis in A Child with Autism

Laurel G Wolf*, Ariel Breitbart, Mileka Gilbert, Patricia McBurney

Department of Pediatrics, Medical University of South Carolina, USA

Corresponding Author

Received Date: May 17, 2021;  Published Date: August 23, 2021


Background: Juvenile Dermatomyositis (JDM) is a rare inflammatory myopathy that classically presents with proximal muscle weakness and classic rashes, however there is a form without rash, “sine dermatitis.” There are also relatively recently described myositis-specific autoantibodies, such as NXP-2 antibody, that can be present in JDM. Variations in clinical presentation and associations of this myositis-specific autoantibody have not been extensively described.

Case Presentation: A 5-year-old female with a history of autism spectrum disorder (ASD) and recent travel to Jamaica presented with 2.5 months of left lower extremity weakness and more recent onset of left upper extremity weakness. Her physical exam was significant for left upper and lower extremity pain and decreased range of motion, absence of skin rash, as well as communication deficits secondary to ASD. She underwent an extensive workup including evaluation for infectious, neurologic, and rheumatologic etiologies of her weakness. Initial laboratory evaluation revealed elevated inflammatory markers, mildly elevated creatine kinase, and positive antinuclear antibody. Magnetic resonance imaging showed evidence of bilateral diffuse myositis with subsequent muscle biopsy of left lower extremity showing signs of an inflammatory myopathy. Further laboratory evaluation was positive for NXP-2 autoantibody associated with JDM. Her clinical picture is most consistent with JDM sine dermatitis. She was treated with steroid taper and methotrexate with improvement in symptoms.

Conclusion: JDM can present in various ways, and clinical suspicion should be high even in patients with misleading historical and physical exam findings. Because JDM is such a rare disease, this case provides important insight into the atypical way that it can present, particularly with a challenging physical exam, and it provides information on clinical manifestations appreciated with the NXP-2 autoantibody.

Keywords: Juvenile dermatomyositis; Dermatomyositis sine dermatitis; Juvenile idiopathic inflammatory myopathy; NXP-2 antibody.

Abbreviations: ASD Autism Spectrum Disorder; ANA Antinuclear Antibody; CK Creatine Kinase; ESR Erythrocyte Sedimentation Rate; LDH Lactate Dehydrogenase; JIIM Juvenile Idiopathic Inflammatory Myopathy; JDM Juvenile Dermatomyositis; JPM Juvenile Polymyositis; AST Aspartate Aminotransferase; ALT Alanine Aminotransferase; EULAR European League Against Rheumatism; ACR American College of Rheumatology

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