The best questions often stem from the inquisitive learner. As educators, we love and  are always humbled by those moments when we get to say “I don’t know.” For some of these questions, you may already know the answers. For others, you may never have thought to ask the question. For all, questions, comments, concerns, and critiques are encouraged. Welcome to the Kids Korner.

Question: Are corticosteroids effective in the treatment of serum sickness-like reactions?

Classic serum sickness is a Type III immune hypersensitivity reaction previously described in patients receiving heterologous serum as an anti-toxin treatment for diphtheria.¹ Today, we see something similar in children called serum sickness-like reactions (SSLR). The exact mechanism is poorly understood and not the same as serum sickness, but the presentation is very similar and often includes an urticarial or erythema multiforme-like rash, fever, and hand and feet swelling with arthralgias. It’s most often secondary to a drug and reported to occur one to three weeks after an exposure. The most common culprits are beta-lactam antibiotics, but other drugs such as sulfonamide antibiotics, anti-cancer agents, anti-convulsants, and antibody biologic agents have been shown to cause it.^1,2

Cefaclor, a second-generation cephalosporin, used to be the most common cause of serum sickness-like reactions in children. According to a prospective observational study, it accounted for about two-thirds of cases.³ Cefaclor is no longer widely used in the United States. While there are numerous case studies in the literature that treat with oral steroids there are—surprisingly—almost no larger studies.

While physicians often treat SSLR with corticosteroids, we are unable to find any prospective studies on treatment for SSLRs.^4,5 The most objective data we were able to find on SSLRs was a retrospective study by Del Pozzo-Magana (2021).¹ This study identified 83 children with SSLR based upon clinical presentation over a 10-year period who received follow up to an Adverse Drug Reactions Clinic at a children’s hospital. Ages ranged from 11 months to 12 years with a median age of two years. Patients with pre-existing rheumatologic conditions were excluded. Amoxicillin was the offending drug in 87 percent (72 out of 83) of cases. The mean time from drug exposure to development of SSLR was 8.5 days. Regarding treatment, 57.8 percent of children received antihistamines and NSAIDS only, while 38.5 percent received antihistamines, NSAIDS, and oral corticosteroids. The mean time to symptom resolution for all children combined was 7.1 days. There was no significant difference in mean time to symptom resolution between children who did (six days) and did not (eight days) receive oral steroids (p=0.09). There was a trend for a shorter recovery but it was not statistically significant.