The Development of Ecchymosis after Administration of Convalescent Serum in a Patient with COVID-19 Associated with Thrombocytosis.

COVID-19 can have an unpredictable and severe course, leading to many hypotheses regarding its pathophysiology and clinical manifestations. Haematological manifestations are a significant predictor of disease severity. The most common observation is lymphopenia with an increased neutrophil:lymphocyte ratio. Platelets have been implicated in thrombogenic events, but the most frequently reported abnormality is mild thrombocytopenia. Here we present an interesting case of a patient with moderate COVID-19 who presented with cutaneous ecchymoses and thrombocytosis, and discuss this paradox. LEARNING POINTS: Bleeding manifestations such as ecchymoses can occur as an idiosyncratic reaction to the administration of convalescent plasma therapy in COVID-19.Thrombocytosis can occur in COVID-19 and could be a contributory factor to disease vasculopathy. © EFIM 2021.