It's not always an infection: Pyoderma gangrenosum of the urogenital tract in two patients with multiple sclerosis treated with rituximab

B-cell depleting therapies such as rituximab and ocrelizumab are widely used for the treatment of Multiple Sclerosis but have increased risks of adverse reactions compared to earlier MS therapies. One rarely reported reaction is pyoderma gangrenosum (PG), an inflammatory, ulcerative, skin disease of unclear etiology. Here we describe a male and female patient, each with Relapsing-Remitting Multiple Sclerosis, and both of whom developed PG while on rituximab. Both PG diagnoses were supported by persistent fever, biopsy reports of sterile neutrophilia, and leukocytosis in the absence of an identifiable infectious agent. The diagnoses were further confirmed by dramatic clinical improvement following initiation of high dose steroids and intravenous immu-noglobulins, and discontinuation of rituximab.

Automated summary

B-cell depleting therapies such as rituximab and ocrelizumab, commonly used for Multiple Sclerosis treatment, have increased risks of adverse reactions, one of which is the rarely reported pyoderma gangrenosum (PG), an inflammatory, ulcerative skin disease. We describe two patients with Relapsing-Remitting Multiple Sclerosis who developed PG while on rituximab, and their diagnoses were supported by clinical symptoms, biopsy reports, and response to treatment.