A 47-year-old married male patient attended the Oral Medicine Department of the Hospital de Clínicas in Porto Alegre and reported having painful lesions in the oral cavity with the appearance of bleeding blisters that rupture easily and leave an ulcerated surface for approximately 4 months. In the anamnesis, the patient states that he is a non-smoker and works in a car battery factory, which has also caused him chronic intoxication (saturnism). He also claims to have had an ulcer on his right leg for 20 years.
Physical examination reveals swollen cervical and submaxillary lymph nodes on the left side, as well as several ulcer-like lesions on the labial mucosa, palate, jugal mucosa, floor of the mouth and larynx. The lesion on the right leg is confirmed, as well as erosive lesions covered by a crust on the axillae and trunk.

A partial biopsy of one of the lesions on the lower lip was performed, in which a positive Nikolsky's sign was observed at the time of biopsy and the histopathological features of the lesion were blisters with suprabasal acantholysis, which is compatible with pemphigus vulgaris.

A few days after the biopsy the patient suffered an exacerbation of the lesions and had to be admitted to hospital with a picture consisting of: blistering lesions on the thorax, right leg and oral cavity, preventing him from eating. He underwent further biopsies of the lesions on the trunk and mouth and an immunofluorescence examination, which showed IgG deposition in the intercellular junctions, IgA in the walls of small vessels and absence of IgM, C3, C1q and fibrinogen deposits. Treatment with prednisone was started with gradually increasing doses up to 100 mg daily. The patient responded favourably to treatment and left the hospital with a marked improvement.

After hospitalisation, treatment was established for the patient based on 140 mg daily prednisone associated with 100 mg Azathioprine, 40 mg Omeprazole, 400 mg calcium carbonate, vitamin D4 and Nystatin rinses, the latter 4 times a day. After one month of treatment, almost complete remission was observed and the prednisone dose was reduced to 120 mg for 15 days and then to 100 mg. It was also decided to increase the dose of Azathiproprine to 150 mg daily. The patient is still under medical supervision.

