Diagnosis of gout

Your GP will ask about your symptoms and examine you. He or she will also ask you about your medical history and that of your family. Your GP will usually take a sample of your blood, which will be sent to a laboratory to measure the levels of uric acid. Your blood sample may also be tested to find out whether there may be another reason for your symptoms. 

Your GP may refer you to a rheumatologist (a doctor specialising in conditions that affect the joints) for further tests.

Your doctor may remove some fluid from your swollen joint with a needle. This usually causes no more discomfort than a blood test. If uric acid crystals can be seen in the fluid under a microscope, you have gout. If calcium crystals are seen, you have a similar condition called pseudogout. The crystals formed when you have pseudogout are made of a calcium salt called calcium pyrophosphate. See our frequently asked questions for more information. 

You may need to have an X-ray of your joint in order to rule out other conditions and to find out if any damage has occurred, but this isn’t used to diagnose gout.

Causes of gout

You can develop gout if you have too much uric acid in your body. Uric acid is a chemical that everyone has in their blood. It's a waste product formed from substances called purines, which are found in every cell in your body and certain foods. Uric acid is formed in your body when the purines in foods you eat are broken down. It’s also formed when old cells in your body are broken down and replaced by new cells. Excess uric acid is passed through your kidneys and out of your body in your urine. However, the level of uric acid in your blood can rise if:

• your kidneys don't pass uric acid quickly enough
• your body produces too much uric acid

If the level of uric acid in your body is too high, it can form tiny crystals that collect in your tissues, particularly in and around your joints. This is what may cause your swelling and pain. These crystals tend to form at a cooler body temperature, which is why gout is more common in your fingers and toes.

You may have high levels of uric acid, but not get gout, or you may get gout, but not have high levels of uric acid. It's not known why some people develop gout and others don't. However, there are certain factors that can increase your likelihood of getting gout. You're more likely to get gout if you:

• are a man aged 30 to 60
• are a woman who has been through the menopause
• eat a diet that contains high levels of purines, which are found in red meat, seafood and some other foods
• drink too much alcohol, especially beer
• don’t drink enough fluids daily and become dehydrated
• take certain medicines, such as diuretics (water tablets), which increase the flow of urine from your body
• have a family history of gout
• have kidney disease meaning that your kidneys don't pass enough uric acid out in your urine
• are overweight, have diabetes or high blood pressure
• have psoriasis (itchy, dry and flaky skin), which can sometimes cause your body to produce too much uric acid
• are taking certain types of cancer medicines

Complications of gout

Having gout won’t always lead to further problems, but you can reduce your risk of having complications by having treatment and making changes to your lifestyle and diet.

The most common complication of gout is progressive joint damage, which leads to long-term pain, deformed joints and eventually, disability. This may be prevented by changes to your diet and by taking medicines that lower your uric acid levels. There is also some evidence that prolonged high levels of uric acid in your body can increase your risk of vascular diseases, which may lead to a heart attack or stroke.

Other complications that you may have are as follows.

• Gout affecting several of your joints (called polyarticular gout). This happens more often in older people with gout.
• Getting kidney stones (if uric acid crystals collect in your urinary tract). This happens to between one and three in 10 people who have gout.
• Damage to your kidneys (if uric acid crystals collect in your kidney tissue).

Symptoms of gout

You may only ever have gout once in your life and it may go away without any treatment.

The first symptoms of gout in your affected joint include:

• severe pain
• swelling and warmth around the area
• red and shiny skin around the area, which may peel later on

You may also have a mild fever.

If you have gout that reoccurs over many years, you may have further symptoms. This can include firm, white lumps developing beneath your skin – these are made of uric acid crystals and are called tophi. Tophi usually take up to 10 years to develop from your first episode of gout. Having tophi can lead to a range of problems, including:

• the tophi becoming inflamed, which can cause discomfort
• tophi breaking down and leaking out a white, paste-like substance

You may want to discuss with your GP treatments to ease discomfort from having tophi. However, taking antibiotics for inflamed or leaking tophi won’t help because tophi aren’t caused by bacteria.

These symptoms may be caused by problems other than gout. If you have any of these symptoms, see your GP for advice.