# Desensitization to Tocilizumab in a Patient With Juvenile Idiopathic Arthritis

## TL;DR

A child with juvenile arthritis developed an allergic reaction to tocilizumab but was successfully treated with a desensitization protocol.

## Contribution

Demonstrates successful desensitization to tocilizumab in a pediatric patient with hypersensitivity.

## Key findings

- The patient experienced a Grade II hypersensitivity reaction after four years of tocilizumab treatment.
- A 12-step desensitization protocol allowed continued therapy without further allergic reactions.
- Intradermal testing confirmed hypersensitivity, while skin prick testing was negative.

## Abstract

Juvenile idiopathic arthritis is the most common chronic inflammatory rheumatic disease in children, classified by the number of affected joints, systemic symptoms, and rheumatoid factor presence. We describe the case of an eight-year-old female with extended oligoarticular juvenile idiopathic arthritis and a strong family history of atopy who developed a Grade II hypersensitivity reaction during a tocilizumab infusion after four years of treatment. Symptoms, including rash, urticaria on the neck and arms, periauricular edema, tachycardia, and hypertension, emerged within 30 minutes of infusion. The reaction was managed with intramuscular epinephrine, intravenous hydrocortisone, and saline, leading to symptom resolution. Skin prick testing was negative, but intradermal testing showed a positive reaction. Due to the drug’s effectiveness in controlling her disease, a desensitization protocol was initiated, involving a 12-step, 5.67-hour infusion schedule with premedication every four weeks. This case highlights the importance of desensitization protocols in patients requiring continued monoclonal antibody therapy despite hypersensitivity reactions.