4 Years Old Boy with Relapsing Juvenile Dermatomyositis without Skin Manifestation

We report a 4-year-old boy with North African Heritage who presented initially with low grade fever, mild pharyngitis and myopathy which had led to myositis diagnosis based on muscle biopsy and MRI findings. He also had positive parvovirus IgG, and elevated inflammatory markers. He responded well to corticosteroid but subsequently experienced two relapses. The first relapse upon withdrawing the corticosteroid treatment. It was controlled by corticosteroid, methotrexate and immunoglobulin therapy. During this relapse he tested positive to streptococcal throat infection. The second relapse followed withdrawal of methotrexate treatment and was again managed successfully with corticosteroids, methotrexate and immunoglobulin treatment as discussed in detail below. Upon reevaluation of the muscle biopsy and repeat MRI findings, the diagnosis was revised to juvenile dermatomyositis (JDM) without dermatological manifestations. This case is notable for the absence of skin involvement, a relapsing disease course, and inconclusive muscle biopsy and bone findings on MRI. Additionally, it highlights the critical role of immunoglobulin therapy in refractory myositis. Our findings suggest that muscle biopsy should be considered for accurate diagnosis in suspected inflammatory muscle disease, even when dermatological symptoms are absent.