Childhood serum sickness: a case report.

Childhood serum sickness is a rare allergic disease that follows the administration of a foreign antigenic material, most commonly caused by injecting a protein or haptenic drug. The disease is a type III hypersensitivity reaction mediated by deposits of circulating immune complexes in small vessels, which leads to complement activation and subsequent inflammation. The clinical features are fever, cutaneous eruptions, lymphadenopathy, arthralgias, albuminuria, and nephritis. Serum sickness is an acute self-limited disease. We report a 3-year-old child who presented with fever and a rash; an invasive bacterial infection was strongly suspected. He was therefore given penicillin and gentamicin and responded well. At day 4 after admission, he developed a serum sickness reaction and showed symptoms of arthralgias, generalized edema, purpura, and gross hematuria. The white blood cell count was 12 190/mm3 with 7% eosinophils. Urinalysis revealed red blood cell above 100 per high power field, white blood cell 10 to 15 per high power field, and proteinuria. The antibiotics were discontinued and hydrocortisone (20 mg/kg/d), diphenhydramine HCl (4 mg/kg/d), aspirin (66 mg/kg/d) was administered, plus 1 dose of epinephrine (0.01 mL/kg) administered intramuscularly. On day 7, the 3rd day after withholding antibiotics, his condition dramatically improved. The clinical symptoms resolved progressively and his urinalysis returned to normal.