Supplementary Material for: A Case of Juvenile Dermatomyositis Presenting with Inverse Gottron’s Papules: A Case Report

Introduction: Inverse Gottron’s papules is an uncommon presentation of dermatomyositis, with a paucity of studies published in children with juvenile dermatomyositis (JDM). Case presentation(s): A five-year-old girl presented with progressive bilateral eyelid erythema and edema, mild erythematous rash over the face, painful palmar papules (inverse Gottron’s papules), and proximal muscle weakness for three months. Additional symptoms included intermittent fever, decreased appetite, joint pain, and mild abdominal pain. Physical examination revealed upper and lower eyelid erythema with mild edema (heliotrope sign), Gottron’s papules over the dorsal distal Interphalangeal joint (DIP), Gottron’s sign over the dorsal metacarpophalangeal (MCP) joints, proximal interphalangeal (PIP) joints, and elbows, Inverse Gottron's sign over the palmar surface of the hands (PIP and DIP), and ragged nailfold cuticles with no dilated capillaries. Laboratory investigations showed elevated muscle enzymes, positive myositis-specific antibodies, and elevated liver function tests. High-resolution computed tomography (HRCT) chest revealed no signs of interstitial lung disease (ILD). Whole-body magnetic resonance imaging (MRI) revealed bilateral upper limb subcutaneous edema and generalized myositis, particularly in the pelvis and thigh muscles, confirming the diagnosis of JDM. Treatment involved intravenous methylprednisolone 30 mg/kg/day for three days followed by tapering, and topical corticosteroids over dermatomyositis-affected areas. Conclusion: Inverse Gottron’s papules is an uncommon cutaneous manifestation of dermatomyositis (DM) that has an association with ILD in both adults and children. Thus, patients with dermatomyositis and inverse Gottron’s papules should be investigated for ILD. Our patient represents the first reported case of JDM with inverse Gottron’s papules in Saudi Arabia.