A case of pediatric serum sickness like reaction (SSLR) after a 2-month re-exposure to amoxicillin

BACKGROUND

Serum-sickness like reactions (SSLRs) to amoxicillin have been documented in the medical literature. Beta-lactams are important and commonly used medications especially in the pediatric population. Often, SSLRs present within days of and during first exposure/ingestion to the offending agent. We described a unique case of a 4-year-old boy who presented with symptoms of amoxicillin SSLR following his second course of amoxicillin with only 2 months and 10 days between his second and first course.

CASE PRESENTATION

A 4-year-old boy presented to hospital with a pruritic rash on day 7 of a 10-day course of amoxicillin for otitis media accompanied by fever (38.7 degrees Celsius). On day 7 of his second course of amoxicillin, which was separated from his first course by only 2 months and 10 days, his mother noticed erythematous, raised, pruritic lesions with central clearing on his sternum. He presented to the ED with emesis, progression of the rash to his torso, back, legs, and face, hypotension, angioedema, and joint pain. His bloodwork demonstrated a leukocytosis of 18.6 × 109 g/L with neutrophilic predominance and thrombocytosis with a platelet count of 653 × 109 g/L. He was treated with 5 mg oral cetirizine daily and 1 mg/kg oral prednisone which improved his rash and angioedema. He was managed with up to 4 times the usual dose of cetirizine. He was assessed in our outpatient clinic as an outpatient and penicillin skin testing was unremarkable. A diagnosis of a probable SSLR to amoxicillin was made.

CONCLUSION

We report an unusual presentation of SSLR following re-exposure to amoxicillin. Our case highlights that patients with previous asymptomatic exposure to amoxicillin can develop SSLR with repeat exposure. Although it is not uncommon for children to develop amoxicillin SSLRs after previous exposure to the drug, this case is unique because of its short time course of 2 months and 10 days months between drug courses. Penicillins are commonly used in the pediatric population. Therefore, it is important to correctly characterize adverse drug reactions to broaden our understanding of SSLRs, prevent unnecessary avoidance of the triggering agent, and improve patient management.

Serum sickness (Like Reaction) in a patient treated with alemtuzumab for multiple sclerosis: A case report

BACKGROUND

Alemtuzumab is a monoclonal antibody approved for relapsing-remitting multiple sclerosis (RRMS). The only report of Serum Sickness (SS) in a MS patient occurred during treatment with natalizumab. Non-protein drugs, such as some antibiotics, may induce "SS-like" reactions (SSLR), whose clinical and laboratory features may partially overlap with the traditional SS.

OBJECTIVE

To report a case of SS/SSLR in a RRMS patient treated with alemtuzumab.

CASE REPORT

A 42-year-old-woman with RRMS developed SS/SSLR in the first week after the first alemtuzumab treatment. Concomitant medications included trimethoprim-sulfamethoxazole at low dose. Intravenous methylprednisolone therapy led to clinical resolution and normalization of serum inflammatory markers.

CONCLUSION

SS/SSLR should be considered in patients treated with alemtuzumab developing delayed fever, rash and arthralgia and differentiated with Infusion Associated Reactions (IARs) and infections.