ABSTRACT
Serum sickness is a type III hypersensitivity reaction mediated by immune complex deposition with subsequent complement activation, small vessel vasculitis, and tissue inflammation. Disease is caused by exposure to foreign proteins, equine diphtheria antitoxin. However, sporadic cases of serum sickness from non-protein antibiotics such as penicillins continue to occur. A retrospective chart review was conducted in 28 children who were admitted because of serum sickness in Mofid Children Hospital since April 2005 to September 2007. Of 28 cases included in our study, 17 were male and 11 female. 24 of the 28 cases [86%] aged less than five years old. In 25 of the 28 patients [89%], the onset of symptoms occurred 1-3 weeks after administration of the inciting antigen, in two patients less than one week, and in one patient more than three weeks. Associated symptoms included arthritis 36%, subjective fever 75%, arthralgia 85%, skin rash and angioedema 100% were observed during admission. Furazolidone was the most common cause of disease in this study. The incidence of serum sickness is decreasing as a result of public health vaccination programs that have decreased the need for specific antitoxins. However, currently, non-protein drugs such as furazolidone are the most common causes of serum sickness-like reactions