Increased incidence of autoimmune haemolytic anaemia with paroxysmal cold haemoglobinuria features in paediatric cases in a changing viral environment post-COVID-19 pandemic.

Paroxysmal cold haemoglobinuria (PCH) is a rare subtype of autoimmune haemolytic anaemia (AIHA) in children. It is characterised by complement-mediated intravascular haemolysis, triggered by biphasic Donath-Landsteiner (DL) antibodies that activate complement against the P antigen of red blood cells. We report four AIHA cases with PCH features, all presenting with haemoglobinuria following an upper respiratory tract infection (URTI). Direct antiglobulin tests confirmed complement fixation without immunoglobulin G binding, as the DL test was unavailable. Treatment consisted of short-term corticosteroids and transfusions. A possible link between increased PCH incidence and pandemic-related changes in viral exposure is suggested. Awareness is crucial for timely diagnosis and early corticosteroid discontinuation.