Successful treatment of pemphigus vulgaris with rituximab in a patient with severe vulvar involvement

Pemphigus vulgaris (PV) is a severe autoimmune bullous disorder characterised by blisters and erosions affecting the skin and mucous membranes. While the oral mucosa is the most commonly affected mucosal site, genital involvement may occur. The frequency of genital involvement is scarcely reported and the response to treatment in patients with severe genital involvement is not well-described. Standard therapy for PV consists of systemic corticosteroids and immunosuppressive agents. Rituximab, a monoclonal antibody directed against the CD20 antigen expressed on B lymphocytes, is used for refractory disease. The efficacy of rituximab has recently been demonstrated in patients with PV; however, its efficacy specifically in patients with predominant and severe genital involvement is not well-described. Herein we report a case of a 72-year-old woman who had severe recalcitrant pemphigus vulgaris characterised by widespread erosions over the trunk and scalp, ulceration of the buccal mucosa, nasal erosions and large vulvar and perianal erosions. Punch biopsy showed suprabasal acantholysis and a mixed inflammatory infiltrate. Direct immunofluorescence showed weak granular intercellar IgG and equivocal staining for C3 consistent with pemphigus. Her disease was refractory to topical therapy and systemic treatment with prednisolone and mycophenolate mofetil. She received two doses, 14 days apart, of rituximab 1g. She had a significant response with resolution of all cutaneous and genital erosions; however, small buccal erosions remained. She remains in remission after 18-months. The efficacy of rituximab in patients with severe genital involvement warrants further research; subgroup analysis in larger observational cohort studies of patients with PV is suggested.

Dr. Nikki Adler