Abstract
We herein report an unusual case of primary Sjögren's syndrome in a 38-year-old woman with typical clinical symptoms (joint pain, dry mouth, and positive Schirmer test) and immunoglobulin G positivity but negativity for antinuclear antibody and all antinuclear antibody spectrum antibodies. Emission computed tomography demonstrated normal ingestion but impaired secretion by the submandibular and bilateral parotid glands. Labial gland biopsy revealed chronic tissue inflammatory changes and Chisholm grade 4 lymphocyte infiltration, confirming primary Sjögren's syndrome. The patient's condition was successfully controlled by nonsteroidal treatment with tacrolimus. Patients presenting with chronic dry mouth should be examined by a Schirmer test, lip gland biopsy, and salivary gland emission computed tomography for possible Sjögren's syndrome, even if serological autoantibodies are negative, to facilitate early intervention. Tacrolimus is a potential treatment option in patients intolerant of steroidal drugs.