Sjogren's (Sjögren's, pronounced SHOW-grins) syndrome is an autoimmune disease in which the immune system targets moisture-producing glands and causes dryness in the mouth and eyes. Other parts of the body can be affected as well, resulting in a wide range of possible symptoms. The disease-fighting cells of the immune system attack the glands that produce tears and saliva (the lacrimal and salivary glands). The disease can affect other glands too, such as those in the stomach, pancreas and intestines, and can cause dryness in other places that need moisture, such as the nose, throat, airways, vagina and skin.

You might hear Sjogren's syndrome referred to as rheumatic disease. A rheumatic disease causes inflammation in joints, muscles, skin or other body tissue, and Sjogren's can do that. The many forms of arthritis, which often involve inflammation in the joints among other problems, are examples of rheumatic diseases. Sjogren's is also considered a disorder of connective tissue, which is the framework of the body that supports organs and tissues (joints, muscles and skin).

It is believed that some 1 to 4 million people have the disease; most - 90% - are women. It can occur at any age, but it usually is diagnosed after age 40 and can affect people of all races and ethnic backgrounds. It is rare in children, but can occur.

Primary versus Secondary Sjogren's Syndrome
Sjogren's syndrome is classified as either primary or secondary. Primary Sjogren's occurs by itself, and secondary Sjogren's occurs with another disease. Both are systemic disorders, although the symptoms in the primary form are more restricted.

In cases of primary Sjogren's syndrome, the doctor can trace the symptoms to problems with the tear and saliva glands. These patients are likely to have different antibodies circulating in their blood compared to people with the secondary form. These antibodies are called SS-A and SS-B; people with primary Sjogren's are also more likely to have antinuclear antibodies (ANAs) in their blood. ANAs are autoantibodies that are directed against the body.

In cases of secondary Sjogren's syndrome, the patient will have had an autoimmune disease such as rheumatoid arthritis or lupus before Sjogren's developed. People with this type tend to have more health problems because they have two diseases, and they are also less likely to have the antibodies associated with primary Sjogren's.

Causes
Researchers believe Sjogren's syndrome is caused by a combination of genetic and environmental factors. Having one of the associated genes will not cause a person to develop the disease without some sort of trigger to activate the immune system.

It is thought that the trigger may be a viral or bacterial infection, and may work like this: A person who has a Sjogren's-associated gene gets a viral infection. The virus stimulates the immune system to act, but the gene alters the attack, sending fighter cells (lymphocytes) to the eye and mouth glands. Once there, the lymphocytes attack healthy cells, causing the inflammation that damages the glands and keeps them from working properly. These fighter cells are supposed to die after their attack in a natural process called apoptosis, but in people with Sjogren's syndrome, they continue to attack, causing further damage. The possibility that the endocrine and nervous systems play a role is also under investigation.

Diagnosis
The doctor will first take a detailed medical history, which includes asking questions about general health, symptoms, family medical history, alcohol consumption, smoking, or use of drugs or medications. The doctor will also do a complete physical exam to check for other signs of Sjogren's.

There may be some tests, too. First, the doctor will want to check the eyes and mouth to see whether Sjogren's is causing the symptoms and how severe the problem is. Because there are many possible causes of dry eyes and dry mouth, the doctor will take these into account.

One is generally considered to have definite Sjogren's if one has dry eyes, dry mouth, and a positive lip biopsy. The doctor may decide to perform additional tests to see whether other parts of the body are affected, and whether various antibodies are found in the blood.