Chronic ulcerative stomatitis (CUS) is an immune-mediated disorder characterized by oral erosions and ulcers usually refractory to conventional treatments. The disease often involves middle-aged and older women with painful lesions sometimes resembling those of erosive oral lichen planus (OLP). The most affected sites are the buccal mucosa, the gingiva and the tongue, but the skin is involved in 22.5% of cases. Histopathologic features in CUS are non-specific and indistinguishable from those of OLP, with the exception of the presence of a mixed infiltrate composed of lymphocytes and plasma cells. Direct immunofluorescence (DIF) analysis reveals the presence of stratified epithelium-specific antinuclear antibodies (SES-ANA) in the lower third of the epithelium. The IgG antibodies detected on DIF are directed against the ∆Np63α isoform of p63 expressed in the nuclei of the epithelial basal cells. A distinguishing feature of CUS is the low response to conventional corticosteroid therapy and the good outcome with hydroxychloroquine at the dosage of 200 mg/day or higher dosages. This paper presents a comprehensive review of CUS and is accompanied by a new case report (the 73rd case) and a proposal for updated diagnostic criteria. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.