Pyodermatitis-pyostomatitis vegetans: a differential diagnosis of pemphigus vegetans.

©2012 by Anais Brasileiros de Dermatologia In the November/December 2011 issue of the Anais Brasileiros de Dermatologia (Brazilian Annals of Dermatology), Adriano et al. reported a case of druginduced pemphigus vegetans (PV). We congratulate the authors on the thorough documentation of the patient as well as on the detailed discussion of the topic. However, we would like to emphasize the importance of considering pyodermatitis–pyostomatitis vegetans (PD-PSV) in the differential diagnosis of PV, given that their clinical presentation and histological findings are similar. PD-PSV is a rare inflammatory disease characterized by pustular and vegetating plaques that affect the skin and mucous membranes. Both PD-PSV and PV present intra and/or subepithelial abscesses with numerous eosinophils and neutrophils on histological examination. The distinction can only be made by immunofluorescence (IF), since direct and indirect IF are normally negative for PD-PSV. However, PD-PSV may show weakly positive direct IF, representing a response to epithelial damage. In spite of the similar immunosuppressant regimen, diagnostic differentiation between PD-PSV and PV is essential. PD-PSV has been described as a highly specific marker of Inflammatory Bowel Disease (IBD), with ulcerative colitis being the most common disorder. Patients with PD-PSV, therefore, must be monitored for early detection of IBD onset and present better dermatologic prognosis. ❑