Idiopathic purpura fulminans with anti-PS antibodies in children: a multicenter case series and systematic review.

Idiopathic purpura fulminans (IPF) is a rare but severe pro-thrombotic coagulation disorder that can occur after chickenpox or HHV6 infection. IPF leads to an autoantibody-mediated decrease in the protein S plasma concentration. We conducted a retrospective multicenter study involving IPF patients from 13 French pediatric centers and a systematic review of literature-published cases. Eighteen patients were included in our case series, and thirty-four as literature review cases. The median age was 4.9 years and the diagnostic delay after the first signs of viral infection was 7 days. The lower limbs were involved in 49 (94%) patients with typical lesions. A recent history of VZV or HHV6 infection was present in 41 (78%) and 7 (14%) of cases, respectively. Most of the patients received heparin (n=51, 98%) and fresh frozen plasma transfusions (n=41, 79%); other treatment options were immunoglobulin infusion, platelet transfusion, corticosteroid therapy, plasmapheresis, and coagulation regulator concentrate infusion. The antithrombin level and platelet count at diagnosis appeared to be associated with severe complications. Given the rarity of this disease, the creation of a prospective international registry is required to consolidate these findings.