Background:  Chronic erosive lesions in the oral cavity are usually difficult to diagnose and treat. Most frequently, the diagnosis is Candida infection, aphtosis, pemphigus or pemphigoid diseases. Chronic ulcerative stomatitis is a common condition of unknown etiology that affects the skin and mucous membranes and has been reported to occur mainly in females over 40 years old. Immunopathological and clinical examinations determine the diagnosis.
Case Report: This study describes the case of a 70-year-old woman with chronic erosive lesions in the oral cavity on the buccal mucosa, tongue and lips. The patient had problems eating, but her general condition was good. Antifungal, antibiotic and local steroid therapy was not effective. We subsequently found disseminated skin and nail lesions characteristic of lichen planus. This suspicion was confirmed by histopathological examination. Other dermatological diseases, including oral lichen planus, pemphigus vulgaris and cicatricial pemphigoid, as well as bullous lupus erythematosus, were excluded. Indirect immunofluorescence (IIF) of the patient’s serum using 2 appropriate substrates (monkey oesophagus at a titre of 1:640 and guinea pig oesophagus at a titre of 1:1280) revealed the presence of squamous epithelium-specific antinuclear antibodies (SES-ANA) of IgG. These are specific immunological markers of CUS.
Conclusions: Hydroxychloroquine, given at a dosage of 400 mg/day, and a low dose of corticosteroids, led to complete remission of the mucosal, skin and nail lesions. A 4-year follow-up of the course of the disease, relapses, remissions and treatment are presented here.

Keywords: chronic ulcerative stomatitis, lichen planus, hydroxychloroquine, corticosteroids