The exact cause of Sjogren's syndrome remains unknown. However, researchers know that the condition is an autoimmune disorder. This means that the patient's immune system attacks healthy tissues by mistake. The body's immune cells begin to attack the glands that secrete moisture, particularly the saliva glands and tear ducts. As a result, patients are unable to produce enough tears or saliva. Eventually cells in other parts of the body, such as the lungs, kidneys, nervous system, or skin, may be attacked.

Researchers have not discovered what triggers this abnormal immune response. Most experts believe that a combination of factors, including genetics, hormones, and infections, may contribute to the development of Sjogren's syndrome.

General: There is no single test to diagnose Sjogren's syndrome. A healthcare provider will first take a detailed medical history and perform a physical examination. The doctor will ask if the patient is taking any medications, such as anticholinergics (medicine that opens the airways by relaxing the muscle bands that tighten around the airways), that may cause side effects similar to Sjogren's syndrome symptoms. If the condition is suspected after a physical examination, a healthcare provider first performs a blood test to determine if abnormal immune cells are present. If these cells are present, additional tests, such as eye tests, imaging studies, and/or biopsies, may be performed to confirm a diagnosis and evaluate the patient's condition.

Fluorescent antinuclear antibody (FANA) test: A blood test, called a fluorescent antinuclear antibody (FANA) test, may be performed if Sjogren's syndrome is suspected. This test detects abnormal antibodies called autoantibodies. These autoantibodies bind to components of an individual's cells and cause the immune system to attack the body. If autoantibodies are present, this suggests that the patient has an autoimmune disorder. However, this test does not determine the specific type of autoimmune disorder that the patient has.

C-reactive protein (CRP) test: The C-reactive protein (CRP) test can be used to monitor inflammation, which is associated with autoimmune disorders. A high or increasing amount of CRP in the blood suggests that the patient has an acute infection or inflammation. In a healthy person, CRP is usually less than 10 milligrams per liter of blood. Most infections and inflammations result in CRP levels higher than 100 milligrams per liter of blood.

While the test is not specific enough to diagnose a particular disease, it can suggest an autoimmune disorder and it can be used to help physicians monitor inflammation and determine if current treatments are effective.

Erythrocyte sedimentation rate (ESR): An erythrocyte sedimentation rate (ESR) test may be conducted to measure and monitor inflammation associated with autoimmune disorders. This blood test measures the rate in which red blood cells settle in unclotted blood.

During an inflammatory response, the high proportion of fibrinogen in the blood causes red blood cells to stick together. The red blood cells form stacks called rouleaux, which settle faster than normal. Elevated levels usually occur in patients who have autoimmune disorders.

Normal values for men younger than 50 years old are 15 millimeters per hour, and normal values for men older than 50 are less than 20 millimeters per hour. The normal values for women who are less than 50 years old are less than 20 millimeters per hour, and the normal values for women older than 50 are less than 30 millimeters per hour.

Like the C-reactive protein test, an ESR test does not suggest a specific diagnosis. However, it is useful in detecting and monitoring tissue death and inflammation.

Schirmer tear test: An eye test, called a Schirmer tear test, may be performed to measure the dryness of the eyes. During the procedure, a small piece of filter paper is placed under the lower eyelid to measure the amount of tears that are produced.

Slit-lamp exam: An eye doctor may use a slit lamp to determine how dry the eye is and whether or not the eye is inflamed. The eye doctor places a drop of colored dye into each eye. The doctor then looks at the patient's eyes using a piece of magnifying equipment, called a slit lamp. The dye stains parts of the eye that have been damaged as a result of dryness.

Imaging studies: A special type of X-ray, called a saliogram, may be performed to determine the condition of the patient's salivary glands. Before the procedure, a colored dye is injected into the patient's parotid glands, which are behind the jaw and in front of the ears. The saliogram produces detailed images of the salivary glands and allows healthcare professionals to see the flow of saliva into the mouth.

Biopsy: A lip biopsy may also be performed to detect the presence of clusters of inflammatory cells, which suggest Sjogren's syndrome. During the procedure a small piece of tissue is removed from salivary glands in the lip and examined under a microscope.

Common symptoms of Sjogren's syndrome include dry eyes, dry mouth, enlarged salivary glands (called the parotid glands), fatigue, dental cavities, difficulty swallowing or chewing, hoarseness, changes in the sense of taste, blurred vision, sensitivity to light, corneal ulcers, skin rash or dry skin, dry cough, vaginal dryness, oral yeast infections, and joint pain or stiffness.

Birth defects: In rare cases, babies born to mothers with Sjogren's syndrome have been born with heart problems. Women with Sjogren's syndrome who are pregnant or plan to become pregnant should discuss the potential risks of childbirth with their healthcare providers.

Inflamed organs: Another uncommon complication of Sjogren's syndrome is inflamed organs. Sometimes internal organs, such as the kidneys, liver, or lungs, may become enlarged. When this happens, the enlarged organs may become infected or lose some functioning. For instance, if the lungs become enlarged, patients have an increased risk of developing bronchitis or pneumonia.

Lymphoma: In rare cases, patients with Sjogren's syndrome may develop cancer of the lymph nodes called lymphoma. Symptoms of lymphoma typically include enlarged lymph nodes, weight loss, fatigue, and night sweats.

Peripheral nervous system disorders: Although uncommon, Sjogren's syndrome may affect the peripheral nervous system and cause peripheral neuropathies. This part of the nervous system allows individuals to feel sensations, such as pain. Patients with peripheral neuropathies may experience numbness, tingling, and burning sensations in the arms and legs. In other cases, the cranial nerves that are in the face and eyes may become damaged. If cranial damage occurs, patients may experience vision problems or facial pain.