Researchers reported a case of a cutaneous drug reaction shortly after the introduction of eculizumab, which is used for disorders such as paroxysmal nocturnal hemoglobinuria (PNH) and neuromyelitis optica spectrum disorder (NMOSD). The case report, published in Clinical Case Reports, noted that a life-threatening desquamating rash after eculizumab administration for PNH has also been reported.

“We report a patient with refractory [NMOSD] who developed a cutaneous drug reaction following intravenous eculizumab administration,” the authors wrote. “This information will be useful to clinicians, given the expanding clinical uses of eculizumab in diseases such as atypical hemolytic uremic syndrome (aHUS), PNH, and myasthenia gravis.”

This case report involved a woman aged 75 years with AQP4-IgG-positive NMOSD. She was undergoing weekly administration of eculizumab after having a poor response to rituximab with mycophenolate mofetil. She developed an itchy rash on all extremities that was unresponsive to diphenhydramine, and eculizumab was discontinued. Oral prednisone 50 mg 4 times daily followed by tapering resolved the rash.

Eculizumab is an immune complement inhibitor that has been approved by the US Food and Drug Administration for the treatment of PNH. Inhibiting the activation of complement with eculizumab reduces the complement system’s inflammatory effects as well as the formation of membrane attack complexes, thereby reducing the hemolysis of erythrocytes in patients with PNH.

Read more about PNH therapies

PNH is a rare genetic disease of pluripotent hematopoietic stem cells that is characterized by hemolytic anemia and hemoglobinuria. It occurs due to a mutation in the phosphatidylinositol glycan class A gene, resulting in a deficiency of the glycosylphosphatidylinositol and leading to hemolysis of hematopoietic stem cells.

The authors note there is limited experience with eculizumab-related drug reactions. However, given the expanding use of eculizumab therapy in a variety of rare conditions, it is important for clinicians to consider cases such as these of potentially life-threatening rashes after initiation of this treatment.


Sharma R, Romo M, Nelson F. Eculizumab-related drug reaction in a patient with neuromyelitis optica. Clin Case Rep. Published online February 8, 2023. doi:10.1002/ccr3.6835