Dryness of the eyes and mouth can have other causes, which include:
- sicca syndrome, which means the glands are less able to make tears and saliva – this can occur as you get older
- conditions other than Sjögren’s syndrome, such as sarcoidosis, which can also damage your tear or saliva-producing glands
- certain medications such as antihistamines and antidepressants
- inflammation of the oil-producing glands in your eyelids (blepharitis), which causes excessive evaporation of the tear film
It’s important to see your doctor to get an accurate diagnosis. Your doctor will ask about your symptoms and carry out tests to assess how dry your eyes and mouth are.
Because there are a number of possible symptoms and complications with Sjögren’s syndrome, it's likely that you'll also need to see an eye specialist (ophthalmologist), a dentist or oral surgeon, or a rheumatologist before you’re diagnosed.
What tests are there?
The main tests that can help with diagnosis are:
Tear production – A small piece of sterilised, pre-packaged blotting paper is used to measure your tear production. This is called Schirmer’s test. The paper is placed in the corner of your eye and folded over your lower eyelid. This is a little uncomfortable and causes your eyes to water, making the paper wet. The amount of water that soaks into the blotting paper within 5 minutes is measured, and this tells the doctor how good your tear production is.
Eye examination – An eye specialist will put a dye (fluorescein and sometimes lissamine green dye) into your eyes and use an instrument called a slit lamp to examine them. The lamp shines a beam of light through a narrow slot (the slit-beam) and magnification allows the doctor to examine the surface of your eye more effectively. This makes it possible to see the film of liquid over the surface of each eye. If you don’t have enough of this liquid, it could be a sign that you have Sjögren’s syndrome.
Saliva production – You may be asked to spit or dribble into a container over a period of 5 minutes or so. The amount of saliva that you can produce in that time is measured.
Ultrasound scans – These are commonly performed now to help diagnose Sjögren’s syndrome. The salivary glands usually have a uniform grey appearance on ultrasound images. In Sjögren’s syndrome, round black areas can be seen in the scans.
X-rays of your salivary glands and ducts (sialography) – A contrast dye is injected so that your glands and ducts show up clearly in the images. This is rarely performed for diagnosis now and is mainly used to identify blockages of the ducts in people who have repeated salivary gland infections.
Other scans – Occasionally magnetic resonance imaging (MRI) scans are used if there is uncertainty over the diagnosis or if lymphoma or other abnormality is suspected.
Blood tests – People with Sjögren’s syndrome often have high levels of antibodies in their blood. These can be measured with blood tests. High antibody levels can make your blood thicker than usual, and this is measured by an erythrocyte sedimentation rate (ESR) test. The ESR measures how fast the cells in a tube of blood settle. The thicker your blood, the faster the cells settle and the higher the ESR.
People with Sjögren’s syndrome often have very high ESR levels regardless of whether they feel well or ill. In Sjögren’s syndrome, the ESR or other measurements of inflammation such as C-reactive protein (CRP) aren't very useful in assessing how active the condition is – unlike in lupus or rheumatoid arthritis.
Two particularly important antibodies are called anti-Ro and anti-La antibodies. They’re found in 75% (anti-Ro) and 40–50% (anti-La) of people with primary Sjögren’s syndrome and can also be seen in patients with lupus. If you have anti-Ro and/or anti-La antibodies along with dry eyes and/or a dry mouth, it’s very likely that you have Sjögren’s syndrome.
Lip biopsy – Several tiny salivary glands may be removed from your lower lip under a local anaesthetic and examined under a microscope. This is increasingly being done to assess the future risk of lymphoma. If there are no early signs then the possibility of developing lymphoma in the future can almost be ruled out. And if the test does suggest a possible risk of lymphoma then this can be monitored and treated as appropriate.
Further specialised tests may be needed if you develop swelling in the lymph glands (in the neck, armpits or groin) or if you have complications involving the chest, kidney, liver or nervous system.