Wolf's post-herpetic isotopic response to tocilizumab for rheumatoid arthritis.

Immediate and delayed hypersensitivity reactions may occur after the first or many exposures to tocilizumab, and they have varying presentations. Here, we describe a Wolf's isotopic response that manifested in a patient as erythema on the same site of a previous healed herpes zoster infection. This phenomenon has rarely been reported in the literature.