PA04 Porcelain papules in paediatrics: a case of systemic Degos disease

Abstract

A previously well 13-year-old boy developed intensely pruritic papules on the trunk and limbs after midge bites during a trip to Scotland 3 years earlier. He later presented with persistent, well-demarcated erythematous pruritic papules on the trunk and upper legs. Dermoscopy revealed central porcelain-white atrophy with telangiectatic rim, and skin biopsy demonstrated central epidermal invagination and dermal collagen necrosis, consistent with hallmark features of Degos disease. Baseline blood tests were unremarkable aside from a low vitamin D level. A vasculitis, autoimmune and viral screen, and imaging including magnetic resonance imaging of the abdomen and brain were unremarkable. The parents sought a second opinion at an international specialist centre in Degos disease and the patient subsequently underwent invasive investigations including a laparoscopy, colonoscopy and gastroscopy. These revealed serosal plaques and mucosal ulcerated lesions throughout the stomach and duodenum, confirming systemic gastrointestinal involvement. A multidisciplinary consensus recommended initiation of complement C5 inhibition with a prostacyclin analogue as adjunctive therapy, corroborated by prior literature confirming prognostic benefit in Degos. He commenced ravulizumab via compassionate access, with no adverse effects to date, and with ongoing paediatric dermatology, gastroenterology, rheumatology and ophthalmology follow-ups in place. Degos disease is a rare thrombo-occlusive vasculopathy that may progress from the limited cutaneous disease (Kohlmeier–Degos) to systemic malignant atrophic papulosis, with gastrointestinal and central nervous system complications causing morbidity and mortality. There are fewer than 50 reported cases of Degos disease in paediatric patients and even fewer reports of systemic Degos reported worldwide. Complement-mediated endothelial injury is implicated, supporting the role of therapeutic C5 inhibition. This case highlights clinicopathological hallmarks enabling early recognition, and the role of the international multidisciplinary team approach in detecting systemic disease. The evidence acts in support of off-­label C5 inhibition, with reduced infusion frequency to improve adherence and holistic outcomes in adolescents.