O08 Severely pruritic juvenile dermatomyositis

Abstract

Abstract A 7-year-old female with type IV skin and autism spectrum disorder presented with a 4 month history of progressive proximal myopathy, weight loss and 20 month history of a worsening, intensely pruritic rash. Cutaneous examination showed a widespread eczematous eruption, post-inflammatory hypopigmentation, heliotrope rash and firm subcutaneous changes, in addition to palmar-plantar papules, pustules and burrows. Extra-cutaneous findings included multiple fixed flexion deformities and muscle wasting. Investigations revealed a normocytic anaemia, elevated muscle enzymes, strongly positive anti-nuclear antibodies and negative myositis-specific antibodies. Whole body MRI reported proximal muscle oedema. Skin biopsy demonstrated lichenoid and perifollicular inflammation, dermal mucin and subcutaneous calcification. Clinical findings were consistent with a diagnosis of juvenile dermatomyositis (JDM), complicated by concurrent scabies. Prednisolone in combination with methotrexate was commenced as first-line therapy in line with current consensus JDM treatment plans, in addition to topical steroids and sun protection. Muscle power started to improve after 5 months but ongoing cutaneous inflammation prompted second-line therapy with IV immunoglobulin. Oral ivermectin was required for the management of scabies due to topical permethrin failure. JDM is a rare autoimmune small-vessel vasculopathy with significant morbidity and limited evidence-based guidelines. Unlike adult-onset disease there is no racial predilection or association with malignancy. Calcinosis is more common in children but early treatment reduces disease complications. JDM has a variable disease course with a median time to remission of 4.67 years. Residual skin changes are increasingly recognised to be an early predictor of prolonged recovery time and these patients may benefit from biologic agents.