Successful desensitization in a patient with adalimumab hypersensitivity

Adalimumab is a fully-humanized monoclonal antibody against tumor necrosis factor alpha (TNF-α) that is used to suppress the immune response. Though rare, hypersensitivity reactions to adalimumab can occur. Desensitization protocols have been developed to safely administer many medications in patients with Type I and Type IV hypersensitivity reactions. This case describes a teenage patient with Crohn's Disease who developed a delayed pruritic urticarial rash hypersensitivity reaction to adalimumab. A novel desensitization protocol was developed based on available literature. Our protocol consisted of four weekly doses, with the first dose in seven steps, second dose in two steps, and two full doses at weekly intervals, before spacing to biweekly injections. This multipart protocol was necessary due to the long half-life of adalimumab, which also allows for maintenance of the desensitized state in between injections. This protocol successfully treated our patient's hypersensitivity to adalimumab, with no further hypersensitivity occurring over a two-year follow-up period.