[1]: 127 Agents that have been implicated in serum sickness–like reactions include cefaclor, amoxicillin, sulfonamides, tetracyclines, ciprofloxacin, nonsteroidal anti-inflammatory drugs, barbiturates, carbamazepine, propranolol, thiouracil, and allopurinol.
Metabolites of these drugs might bind with tissue proteins inappropriately, eliciting an acute inflammatory response that typically develops 7–14 days after initiation of the offending agent.
True serum sickness, a type III hypersensitivity reaction, results in fever, lymphadenopathy, arthralgias, cutaneous eruptions, gastrointestinal disturbances, proteinuria, and significant decreases in serum complement levels; it was originally described after patients were infused with equine immunoglobulins.
The reaction generally includes a constellation of fever; urticarial polycyclic wheals (a rash that can look similar to hives with small swellings that overlap each other [2]) with central clearing on the trunk, extremities, face, and lateral borders of the hands and feet; oral edema without mucosal involvement; lymphadenopathy; arthralgias; myalgias; and mild proteinuria.
While optimal treatment strategies for serum sickness–like reactions are not clearly defined in the literature, discontinuation of the suspected agent combined with use of antihistamines, corticosteroids and NSAIDs for symptom control is an appropriate therapeutic route.