Presumed Serum Sickness Following Thymoglobulin Treatment of Acute Cellular Rejection of a Cardiac Allograft

Serum sickness is a hypersensitivity reaction to proteins in antiserum derived from nonhuman animal sources and can be seen in patients being treated with antiserum to prevent transplant rejection. Serum sickness may display variable clinical presentations. Because cutaneous findings may be the initial symptom in some cases, it is important for dermatologists to be able to recognize this condition given its potentially life-threatening symptoms. We present a case of a 35-year-old man with presumed serum sickness after receiving thymoglobulin for the treatment of acute cellular rejection of a heart transplant. The clinical presentation, laboratory findings, and treatment options are reviewed.