Paroxysmal Cold Hemoglobinuria: Mild to Catastrophic-Spectrum of a Rare Hemolytic Anemia of Childhood.

Paroxysmal cold hemoglobinuria (PCH) is among the rarest forms of autoimmune hemolytic anemia, most often seen in young children. PCH is caused by a biphasic immunoglobulin G antibody that binds to red cells at low temperatures and causes complement-mediated lysis as the temperature is raised. Diagnosis is based on high clinical suspicion followed by confirmation of the presence of Donath-Landsteiner antibodies. We have described 3 cases diagnosed with PCH over a span of 1 year, 2 cases presented with acute kidney injury with variable severity and needed hemodialysis. Another case showed prompt recovery with supportive treatment, suggesting variable severity of PCH. This report intends to generate awareness of this rare condition which is often misdiagnosed as nonspecific autoimmune hemolytic anemia and leads to unnecessary prolonged immunosuppressive therapy. It also emphasizes the rare possibility of the need for prompt renal replacement therapy in an otherwise benign self-limiting disorder.