Small vessel vasculitis
Vasculitides are a distinct group of disorders characterized by inflammation of blood vessels of varying sizes, which leads to obstruction of the vascular lumen. Classification for vasculitides adopted at the International Chapel Hill Consensus Conference 2012 is currently considered as the gold standard. The Paediatric Rheumatology European Society in collaboration with the European League Against Rheumatism and Paediatric Rheumatology International Trials Organization have put forward a classification for childhood vasculitis. Several etiological factors have been identified, which include drugs, infections, systemic diseases, malignancy, and rarely dietary factors. Cutaneous manifestations include palpable purpura and/or petechiae, nodules, hemorrhagic bullae, superficial ulceration, and digital gangrene. Lesions occur in a symmetrical distribution on the dependent areas such as the legs but can occur on the trunk and upper limbs. Although often asymptomatic, there may be pruritus, burning sensation, or pain. The lungs, kidneys, gastrointestinal tract, musculoskeletal, and peripheral and central nervous systems may be involved as a part of the systemic process of vasculitis. The emergencies include acral gangrene, skin necrosis, rapidly progressing glomerulonephritis, alveolar hemorrhage, intussusception, gangrene of the gut, bowel perforation, gastrointestinal hemorrhage, and cerebrovascular accidents. Biopsy with direct immunofluorescence is essential for diagnosis. Management depends on the severity of symptoms and extent of systemic involvement.