Purpura Associated With Lithium Intoxication

A 51-year-old male with bipolar disorder experienced purpura, a skin condition characterized by red or purple discolorations, after being treated with lithium carbonate, despite his blood lithium levels being within the therapeutic range (1.01 mmol/L). This case suggested that lithium could cause purpura through immune complex-mediated mechanisms, where lithium acts as a hapten, triggering an antigen-antibody reaction. The patient's condition improved after discontinuing lithium and administering mannitol, reducing his lithium levels to 0.59 mmol/L. This case underscored the importance of monitoring patients for signs of lithium intoxication, even when blood levels are within the normal range, as skin reactions to lithium, though common, can usually be managed.