Discussion
Cutaneous adverse drug reactions usually start 12-24 hours after exposure.4 A temporal relationship between introduction of eculizumab and development of skin rash suggests a relationship between them.
A study evaluating the immunogenicity of eculizumab found zero of 75 patients with PNH on eculizumab developed human antihuman antibodies.5
Our knowledge of eculizumab-related drug reactions is limited, and further research is needed to better understand the pathophysiology. Importantly, there is little evidence documenting autoimmune response to IgG2/IgG4 monoclonal antibody therapy. Eculizumab’s use in disorders like NMO, aHUS, PNH, and myasthenia gravis makes it important for clinicians to be aware of its potential to cause severe skin reactions. It is possible that this patient’s history of other autoimmune disorders (DLE and Sjogren’s syndrome) played a role in her reaction which is important given that this is common in patients with NMO.