Sjogren's syndrome is a disorder of the immune system (the body's defence system against infection). White blood cells attack the body's tear and saliva glands, which reduces the amount of saliva and tears produced. This causes a dry mouth and dry eyes, along with other related symptoms.
In women (who are most commonly affected), the glands responsible for keeping the vagina moist can also be affected, leading to vaginal dryness.
Sjogren's syndrome is an autoimmune disease. This term refers to any disease caused by a faulty immune system attacking the body's healthy cells and tissues (see box, left).
Primary and secondary disease
Health professionals classify Sjogren's syndrome as either:
- primary Sjogren's syndrome, when the condition develops by itself and not as the result of another condition
- secondary Sjogren's syndrome, when the condition develops in combination with another autoimmune condition, such as lupus or rheumatoid arthritis (see box, left)
The cause of Sjogren's syndrome remains unknown, but research suggests that the condition is triggered by a combination of genetic, environmental and possibly hormonal factors
How common is Sjogren's syndrome?
Sjogren's syndrome is a relatively common condition. In the UK, 3-4% of adults are thought to be affected, and it is likely to be the same in Ireland. This makes it the second most common autoimmune condition after rheumatoid arthritis. However, the condition remains under recognised and often under treated.
Sjogren's syndrome can develop at any age, but most cases begin in people aged 40-60 years old. It is most common in women, who account for 9 out of 10 cases.
There is no cure for Sjogren's syndrome, but a number of treatments can help control symptoms. These include eye drops and medicines to stimulate saliva production.
Complications of Sjogren's syndrome include tooth decay, non-Hodgkin's lymphoma and eye damage from corneal ulcers
Early diagnosis and treatment can reduce the risk of complications and improve the quality of life for people with Sjogren's syndrome. However, the disorder is often under diagnosed because the symptoms are common of many other conditions.
In Sjogren's syndrome, the immune system usually targets the tear and saliva glands.
What is an autoimmune condition?
Your immune system usually helps protect the body from infection and illness by making cells known as antibodies. Antibodies attack bacteria and viruses, which help prevent you from becoming ill.
An autoimmune condition causes your immune system to react abnormally. Instead of attacking foreign cells, such as bacteria, the antibodies start attacking your body's healthy cells and tissue.
In the case of Sjogren's syndrome, the tear and saliva glands are attacked.
Other autoimmune conditions include:
- rheumatoid arthritis (which leads to pain and swelling in the joints)
- lupus (which leads to joint pain, fatigue and skin rashes)
- Hughes syndrome (where proteins and fats in the blood are attacked, leading to blood clots and recurring miscarriages)
The most commonly reported symptoms of Sjogren's syndrome are a dry mouth and dry eyes, both of which can lead to other associated symptoms (see below).
Many women also experience dryness of the vagina, which can make sexual intercourse painful.
Associated symptoms of dry mouth
Associated symptoms of dry mouth include:
- tooth decay, leading to an increased risk of tooth loss
- dry cough
- difficulty swallowing and chewing
- hoarse voice
- difficulty speaking
- swollen salivary glands (located between your jaw and your ears)
- repeated fungal infections of your mouth (oral thrush), symptoms of which include the appearance of white, cream-coloured or yellow spots on the inside of your mouth and tongue
Associated symptoms of dry eyes
Associated symptoms of dry eyes include:
- a burning or stinging sensation in your eyes
- itchy eyes
- a feeling that there is a piece of sand or gravel in your eyes
- irritated and swollen eyelids
- sensitivity to light (photophobia)
- tired eyes
- a discharge of mucus from your eyes
Symptoms can become worse when you are in a windy or smoky environment. Air-conditioned buildings and travelling on aeroplanes can also make symptoms worse.
Other symptoms of Sjogren's syndrome
In more serious cases of Sjogren's syndrome, the immune system can attack other parts of the body as well as the tear, saliva and vaginal glands, causing a wide range of symptoms such as:
- dry skin
- muscle pain
- joint pain, stiffness and swelling
- pain and numbness in certain parts of the body, usually the arms or legs (periphery neuropathy)
- restricted blood flow to the hands, which can cause the hands to feel cold, numb and painful (Raynaud's phenomenon)
- vasculitis (inflammation of blood vessels)
The immune system
The immune system is designed to recognise any foreign object that presents a threat to the body, such as a virus or bacterium, and to attack it with special chemicals known as antibodies (produced by white blood cells).
In Sjogren's syndrome, the immune system mistakes healthy tissue for a foreign body and attacks it with antibodies. The parts of the body usually affected are the tear, saliva and vaginal glands, which are collectively known as the exocrine glands.
The antibodies damage the exocrine glands so that they can no longer function normally. There is also some evidence that the immune system damages the nerves that control these glands, further reducing their effectiveness.
The immune system can go on to damage other parts of the body such as muscles, joints, blood vessels, nerves and (less commonly) organs.
Possible triggers for Sjogren's syndrome
Primary Sjogren's syndrome
The exact cause of Sjogren's syndrome is unknown but most researchers believe it is triggered by a combination of genetic and environmental factors.
The general thinking is that certain people are born with specific genes that make them more vulnerable to a faulty immune system. Then many years later, an environmental factor (most likely a virus such as the Epstein-Barr virus or hepatitis C virus) triggers the immune system to stop working properly.
The female hormone oestrogen seems to play an important role as well. Sjogren's syndrome mostly occurs in women, and symptoms usually start around the time of the menopause, when levels of oestrogen begin to fall. This may suggest that a reduction in oestrogen somehow disrupts the normal functioning of the immune system. Exactly how this occurs is unclear.
Secondary Sjogren's syndrome
Sjogren's syndrome can occur later in the course of other autoimmune conditions, such as rheumatoid arthritis or lupus. This is known as secondary Sjogren's syndrome.
If you have one of these other conditions, you will already be under the care of a specialist who will diagnose Sjogren's syndrome when you start experiencing eye and mouth dryness.
The importance of exocrine glands
The reason that Sjogren's syndrome can cause such a wide range of troublesome symptoms is that your saliva and tear glands play a vital role in protecting your mouth and eyes.
The importance of tears
We usually only notice our tears when we cry. But our eyes are always covered by a thin layer of tears, known as a tear film.
Tears are made up of a mix of water, proteins, fats, mucus and infection-fighting cells. Tears serve several important functions:
- lubricating the eye, keeping it clean and free of dust
- protecting the eye against infection
- helping to stabilise your vision
The importance of saliva
Saliva also serves several important functions, including:
- keeping the mouth and throat naturally lubricated
- aiding digestion by moistening food and containing enzymes that can break down certain starches
- acting as a natural disinfectant (saliva contains antibodies, enzymes and proteins that protect against some common bacterial and fungal infections)
Sjogren's syndrome can be difficult to diagnose as the symptoms are similar to those of other health conditions.
Also, you may see different health professionals for your different symptoms, such as a dentist for a dry mouth, an optician for dry eyes and a gynaecologist for a dry vagina, which can make it harder to reach a firm diagnosis.
See your GP if you experience any symptoms of dryness, especially of your eyes and mouth.
Experts in the field have come up with a series of screening questions, which may be useful if you are worried you may have Sjogren's syndrome.
If you answer yes to most of the questions below, you may have Sjogren's syndrome and will probably be advised to go for further testing by your GP.
- Have you had daily, persistent, troublesome dry eyes for more than three months?
- Do you keep having a sensation of sand or gravel in your eye?
- Do you need to use eye drops containing tear substitutes more than three times a day?
- Have you had a daily feeling of dry mouth for more than three months?
- Do you keep getting swollen salivary glands (located between your jaw and your ears)?
- Do you frequently drink liquids to help you swallow food?
Sjogren's syndrome can usually be diagnosed by looking at the results of the screening questions and carrying out a number of clinical tests. These may include:
- the Rose Bengal and Schirmer tests
- a lip biopsy
- blood tests
- salivary flow rate
These are discussed below.
The Rose Bengal and Schirmer tests
These two tests are usually carried out by an ophthalmologist (a doctor who specialises in the treatment of eye conditions).
The Rose Bengal test is used to measure how effective your tear glands are. A non-toxic dye known as Rose Bengal is dropped onto the surface of your eye. The distinctive colour of the dye allows the ophthalmologist to see how well your tear film is functioning and how long it takes for your tears to evaporate.
In the Schirmer test, small strips of blotting paper are placed under your eyelid. After five minutes, the strips are removed and then studied to see how much of the paper was soaked with tears.
During a lip biopsy, a small sample of tissue is removed from your inner lip and examined under a microscope. You will be given an injection of local anaesthetic into the inner surface of your lower lip (which numbs the area), then a small cut is made to remove a few of your minor salivary glands.
Clusters of lymphocytes (a type of white blood cell) in the tissue can indicate the presence of Sjogren's syndrome.
Blood tests are carried out to look for special antibodies known as anti-Ro and anti-La (or SS-A and SS-B), which are known to be produced when the immune system has been affected by Sjogren's syndrome.
However, the antibodies are only present in about 60% of patients with Sjogren's syndrome, so it is possible to have a negative blood test result and still have the condition.
Salivary flow rate
During this test, you are usually asked to spit as much saliva as you can into a cup over a five-minute period. The amount of salvia is then weighed. The test is a good way of measuring how much saliva your glands are producing each minute. An unusually low flow rate can indicate Sjogren's syndrome.
Mild to moderate cases of dry eye can usually be successfully treated with eye drops that contain 'artificial tears', a liquid that mimics tears. These eye drops are available from a pharmacist without a prescription.
There are many different types of eye drops, so you can try different brands to find the one that works best for you.
A short-term dose of eye drops containing corticosteroids may be recommended if your eyes become severely irritated. However, long-term use of corticosteroids is not recommended as they can cause serious side effects, such as Cushing's syndrome, a rare hormonal disorder that causes sudden weight gain and bloating around the chest and stomach.
To minimise the chance of any side effects from corticosteroids, you will be prescribed the lowest effective dose for the shortest possible time.
Moisture chamber spectacles
Some cases of dry eye can be treated with specially made glasses known as moisture chamber spectacles. These wrap around the eyes much like goggles and help retain moisture and protect the eyes from irritants.
Moisture chamber spectacles used to be unpopular as they had a strange design and people were embarrassed to wear them. Now they are becoming a more popular treatment option as the modern designs look like sports sunglasses.
If your dry eyes fail to respond to other forms of treatment, surgery may be an option.
One widely used technique is punctual occlusion, which involves using small plugs to seal the tear ducts into which the tears drain. This should help keep the eye better protected by tears.
Temporary plugs made of silicone are normally used first to see if the surgery has a positive effect. If it does, more permanent plugs can be used to replace the silicone plugs.
Looking after your mouth
You can use a number of techniques to keep your mouth lubricated and to deal with any associated symptoms, including:
- maintaining good oral hygiene to prevent tooth decay and gum disease
- increasing your fluid intake
- using sugar-free chewing gum to stimulate the production of saliva
- sucking ice cubes to help lubricate your mouth and reduce dryness
- regularly using mouth rinses to soothe the mouth and protect it against infection
If you are a smoker, you should give up. Smoke both irritates the mouth and increases the rate at which saliva evaporates (see the Health A-Z topic on Quitting smoking for advice).
There are a number of saliva substitute products that can help lubricate your mouth. However, they do not replicate the role of saliva in preventing infection, so you will still need to maintain excellent oral hygiene.
Saliva substitutes are available as a spray, lozenge (medicated sweet), gel or gum. Your GP or pharmacist can tell you which product is most suitable for you.
Medication for Sjogren's syndrome
The medicine pilocarpine is often used to treat the symptoms of dry eyes and mouth. Pilocarpine stimulates the tear and saliva glands to produce more saliva and tears.
Side effects of pilocarpine include:
- excessive sweating
- abdominal (tummy) pain
- an increased need to go to the toilet
Less common side effects include:
- high blood pressure
- blurred vision
Blurred vision and dizziness can affect your ability to do skilled tasks such as driving or operating heavy machinery. Avoid such tasks if you experience these side effects.
For some people, the side effects of pilocarpine are mild. Others find that the side effects outweigh the benefits.
Do not take pilocarpine if you have asthma or chronic obstructive pulmonary disease (COPD), or if you are pregnant or breastfeeding.
You may also be recommended a medicine called hydroxychloroquine. Hydroxychloroquine has been shown to slow the immune system's attack on the tear and saliva glands. It can also help reduce any associated symptoms of muscle and joint pain and stiffness.
You will need to take hydroxychloroquine for several weeks before you notice any improvements and it could be six months before you experience the full benefit of the treatment.
Side effects are uncommon and usually mild, including:
- skin rash
- loss of appetite
- stomach cramps
In very rare cases, hydroxychloroquine can damage the retina, affecting vision. You will probably be asked to attend an eye examination so the state of your retina can be checked before you start treatment. Regular eye examinations (usually at least once a year) are also recommended after you begin treatment.
Hydroxychloroquine should not be used by pregnant and breastfeeding women.
Treating other symptoms of Sjogren's syndrome
Several soaps and creams are especially designed for people with dry skin. Your pharmacist or GP can advise you.
The symptoms of vaginal dryness can be treated using a lubricant, such as KY Jelly. Some women also consider using oestrogen creams or hormone replacement therapy (HRT).
Muscle and joint pains
Muscle and joint pains can be treated with an over-the-counter non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen. If this does not work, see your GP as stronger NSAIDs are available on prescription.
NSAIDs can increase your risk of developing stomach ulcers and internal bleeding, particularly if they are taken on a long-term basis. Ideally, take NSAIDs with food or shortly after eating. This will help minimise the risk of the medicine upsetting your stomach.
If you find swallowing NSAIDs difficult because of your dry mouth, you can try an NSAID cream that is rubbed into affected joints.
NSAIDs are not recommended for women who are pregnant or breastfeeding, or for people with pre-existing risk factors for cardiovascular or kidney conditions.
General advice for people with Sjogren’s syndrome
- Have a dental check-up every six months.
- Practise good dental hygiene, brushing, flossing and using mouthwash regularly.
- Avoid eating too many sweet foods.
- Avoid strong and perfumed soaps. Use special creams and soaps from your pharmacist.
- Avoid dry environments (such as air-conditioned offices) where possible.
- Stop smoking and do not drink too much alcohol.
It is estimated that people with Sjogren's syndrome are 44 times more likely to develop non-Hodgkin's lymphoma than people without Sjogren's syndrome.
Non-Hodgkin's lymphoma is a cancer of the lymphatic system. The lymphatic system is a series of vessels and glands (lymph nodes) that are spread throughout your body, much like your blood vessels.
While this increased risk may sound alarming, the chance of a person with Sjogren's syndrome developing non-Hodgkin's lymphoma is still unlikely, and it affects about 5% of patients.
If you have Sjogren's syndrome, be alert for the main early symptom of non-Hodgkin's lymphoma, which is a painless swelling in a lymph node (gland), usually in the neck, armpit or groin. Report any swollen lymph nodes to your GP.
If dry eyes are not treated, they can lead to infection and the development of ulcers on the surface of the eyes, called corneal ulcers.
If left untreated, corneal ulcers can lead to loss of vision and permanent damage to your sight.
If you are planning to become pregnant and have Sjogren's syndrome, ask your GP to test for certain antibodies that may be present in Sjogren's syndrome and are known to cause lupus in newborn babies. In very rare cases, the antibodies can also cause heart defects in babies.
If these antibodies are found, there should be no reason why you cannot proceed with the pregnancy, but your child may need additional specialist care during pregnancy and after the birth.