Pediatric emergency medicine trisk 1682 1682

Clinical Recognition The history should be directed toward identifying the offending agent (including potential exposures up to weeks before symptom onset), prior antigen exposures, and reaction severity Characteristically, symptoms develop to 14 days after the primary exposure; however, among patients with prior sensitization symptoms may develop within a few days of antigen reexposure Given there is significant variation in clinical manifestations and reaction severity among patients with serum sickness, a thorough history, review of systems, and physical examination is required to exclude systemic involvement Findings typically include fever, malaise, rash (urticarial, maculopapular, or vasculitic), arthralgias, arthritis (joint swelling, warmth), lymphadenopathy, angioedema, and nephritis (hematuria, edema, oliguria) Less common features include abdominal pain, hepatosplenomegaly, carditis (friction rub, new murmur, gallop), wheezing, pallor, and neurologic deficits secondary to CNS vasculitis Serum sickness–like reactions are generally limited to fever, pruritis, urticarial rashes, and arthralgias Reactions are usually self-limited and typically resolve within to weeks Laboratory Assessment Laboratory evaluation should be guided by reaction severity, evidence of organ system involvement, and the degree of diagnostic uncertainty In the majority of cases it is appropriate to limit diagnostic testing to a urinalysis to exclude nephritis A list of other diagnostic tests to evaluate for complications from immune complex–mediated disease is outlined in Table 85.2