A Longitudinal Case Study of Recurrent Pyostomatitis-Pyodermatitis Vegetans Followed by the Subsequent Development of Bullous Pemphigoid With the Presence of Anti-BP230 Autoantibodies Six Years Later.

Pyostomatitis vegetans (PSV) is a rare inflammatory condition that has been strongly associated with inflammatory bowel disease (IBD). Additionally, certain cases of PSV have been reported to co-occur with pyodermatitis vegetans (PDV), resulting in a distinct mucocutaneous manifestation. Herein, we present a clinical case of PSV in a 64-year-old male patient diagnosed with ulcerative colitis (UC). The oral lesions demonstrated complete resolution following treatment with systemic glucocorticoids and immunosuppressants, in conjunction with targeted therapy for the underlying intestinal disease. During longitudinal follow-up, the patient subsequently developed PDV and, unexpectedly, exhibited recurrent bullous eruptions on cutaneous surfaces, specifically localized to the axillary and dorsal regions six years post-initial diagnosis. Enzyme-linked immunosorbent assay (ELISA) analysis revealed significantly elevated titers of circulating anti-BP230 antibodies in the serum samples. These clinical and immunologic findings, together with histopathological evaluation of the cutaneous lesions, established an additional diagnosis of bullous pemphigoid (BP). Both BP and PSV-PDV conditions remained clinically stable under treatment with topical and systemic glucocorticoids, with circulating anti-BP230 antibody titers normalizing eight months after the initiation of therapy. To the best of our knowledge, this represents the first documented case of a patient with PSV-PDV developing BP mediated by anti-BP230 antibodies during long-term follow-up observation. This finding underscores a potential novel disease association that warrants further exploration.