Post-EBV Cold Urticaria with High-Titre Cold Agglutinins without Haemolysis: A Paediatric Case Report

This report describes a paediatric case of cold urticaria (ColdU) associated with markedly elevated cold agglutinin titres following Epstein-Barr virus (EBV) infection. An 11-year-old girl developed recurrent cold-induced urticaria and anaphylaxis after a recent EBV infection. Immunohaematologic testing revealed a cold-reactive IgM autoantibody with anti-i specificity. Despite the exceptionally high peak titres (>1:262,144 at 4°C), and the unusually broad thermal amplitude extending to 30°C, no clinical or laboratory evidence of haemolysis was observed, and the direct antiglobulin test remained persistently negative. Complement components and cryoprotein assays were consistently normal. Throughout an extended 52-month longitudinal follow-up, antibody titres gradually declined in parallel with the resolution of urticarial symptoms and withdrawal of antihistamines. This case demonstrates a non-haemolytic, post-infectious immune phenotype of ColdU, in which transient, high-titre cold agglutinins coexist with cutaneous hypersensitivity without haemolytic manifestations, and highlights the importance of comprehensive immunohaematologic evaluation and long-term monitoring in ColdU cases with atypical serologic findings.