Serum sickness, a reaction presenting with a classic triad (fever, rash, myalgia/arthralgia) and considered as a rare adverse event following monoclonal antibodies and specifically following treatment with rituximab. This report describes a case of serum sickness in a newly treated young male patient with rituximab for pemphigus vulgaris.

Serum sickness, a reaction characterized by fever, rash, myalgia, and arthralgia, can occur in patients who receive chimeric monoclonal antibody therapy. Serum sickness is considered as a rare adverse event following rituximab therapy. We report a case of serum sickness in a newly treated patient with rituximab for pemphigus vulgaris.