A case of juvenile dermatomyositis manifesting inflammatory epidermal nevus-like skin lesions: unrecognized cutaneous manifestation of blaschkitis?

ABSTRACT Background Juvenile dermatomyositis is potentially life threatening rare autoimmune illness that mainly affects muscle and skin. Cutaneous features are useful in establishing the diagnosis of this disease. Case Summary We report an 8-year-old male juvenile dermatomyositis who presented epidermal nevus like- lesions on the back of the right thigh. Characteristic cutaneous changes such as Gottron's papules of the hand, heliotrope rash of the eyelids, and poikiloderma-like lesions on the back were observed. Diagnosis of juvenile dermatomyositis was made by positive muscle biopsy and magnetic resonance imaging findings and typical cutaneous manifestations. However, epidermal nevus-like skin lesions, an acquired inflammatory dermatosis that follows Blaschko lines, seen in this case have been rarely reported in the literatures. Discussion We would like to report this case and discuss about the significance and pathogenesis of this rare cutaneous manifestation like Blaschkitis in juvenile dermatomyositis.