109 - Pediatric Serum-like Sickness: a multicenter analysis

Serum sickness-like reaction (SSLR) is a type III immune hypersensitivity reaction that presents 5-21 days following exposure to a medication. SSLR has nonspecific symptoms including fever, rash, and joint involvement. There are no standardized diagnostic criteria or treatment for SSLR, making this a challenging diagnosis.

Objective: Our objective was to describe pediatric SSLR clinical manifestations, medical encounter types, and treatment strategies.

Design/Methods:

A retrospective chart review across 2 freestanding children’s hospitals was used to identify patients 0-21 years of age diagnosed with SSLR by ICD-9/10 codes [T80.69XA, 999.59], SNOMED codes [1782626019, 3293325014], or pharmacovigilance review in the emergency department and inpatient setting between January 1, 2015–December 31, 2021. Patients with SSLR to biologics, vaccines, and chemotherapy were excluded. A comprehensive set of clinical data were obtained including subject demographic information, implicated medication, indication of implicated medication, SSLR clinical symptomatology, frequency of health care encounters associated with SSLR diagnosis, treatment, and clinical consultations.

Results:

A total of 201 children were diagnosed with SSLR (Table 1). Two hundred cases were associated with an antibiotic; 1 case was associated with an antiepileptic. Amoxicillin or amoxicillin-clavulanate were the most commonly implicated medications (80%). Acute otitis media was the most common indication for antibiotic use in 60% of cases. Seventy-five patients (37%) presented with SSLR symptoms following completion of treatment. The most common clinical symptoms were rash (199; 99%), joint involvement (80%) and fever (39%). On average, children experienced 1.9 healthcare visits due to symptoms until SSLR on differential. Eight-six (43%) children were hospitalized. Medical consultation occurred in 70 cases (35%), most commonly dermatology (14%) and infectious diseases (10%) (Table 2). The majority were treated with supportive care only including antihistamines, acetaminophen, and ibuprofen. Additional treatments were systemic steroids (52%), acid reducer (21%), and epinephrine (4.5%).

Conclusion(s):

To our knowledge, this is the largest study describing pediatric SSLR. Diagnosis is difficult often requiring more than one medical care visit before SSLR was in the differential. Variability in clinical symptoms as observed. Although SSLR is self-resolving, many children received steroid therapy. Future work is needed to standardize the diagnosis and treatment of pediatric SSLR to help minimize diagnostic challenges and unnecessary therapies.