Sarcoidosis is a rare condition that causes small patches of red and swollen tissue, called granulomas, to develop in the organs of the body. It most often affects the lungs and skin.
Typical symptoms include tender, red bumps on the skin, shortness of breath and a persistent cough. However, every person is affected differently and symptoms depend on which organs are affected.
There's no cure for sarcoidosis, but the condition often improves without treatment within a few months or years. The symptoms are not usually severe and don't tend to affect everyday life.
Sarcoidosis is estimated to affect about 1 in every 10,000 people in the UK.
Symptoms of sarcoidosis
It's impossible to predict how sarcoidosis will affect a person, as the condition can affect any organ and the symptoms vary widely depending on which organs are involved.
Most people with sarcoidosis develop symptoms suddenly, but they usually clear within a few months or years and the condition doesn't come back. This is known as acute sarcoidosis.
Some people do not have any symptoms at all, and the condition is diagnosed after an X-ray carried out for another reason.
A few people find that their symptoms develop gradually and get worse over time, to the point where they become severely affected. Lots of granulomas may form in an organ and prevent it from working properly. This is known as chronic sarcoidosis.
Sarcoidosis most often affects the lungs, skin and/or lymph nodes (glands). Some of the typical symptoms are listed below, although someone with sarcoidosis will probably only have a few of these.
The lungs are affected in about 90% of people with sarcoidosis. This is known as pulmonary sarcoidosis.
The two main symptoms are shortness of breath and a persistent dry cough. Some people with pulmonary sarcoidosis experience pain and discomfort in their chest, but this is uncommon.
The skin is affected in about 25% of people with sarcoidosis.
This can cause tender, red bumps or patches to develop on the skin (particularly the shins), as well as rashes on the upper body.
If other organs are affected, you may also have some of the following symptoms:
Causes of sarcoidosis
The body's immune system normally fights off infections by releasing white blood cells into the blood to isolate and destroy the germs. This results in inflammation (swelling and redness) of the body tissues in that area. The immune system responds like this to anything in the blood it doesn't recognise, and dies down when the infection has been cleared.
It is thought that sarcoidosis happens because the immune system has gone into "overdrive", where the body starts to attack its own tissues and organs. The resulting inflammation then causes granulomas to develop in the organs.
There are many similar conditions, such as rheumatoid arthritis and lupus, that are caused by the body attacking its own tissues. These are collectively known as autoimmune conditions.
It is not known why the immune system behaves like this, but research is being carried out to see what triggers sarcoidosis (search clinical trials for sarcoidosis).
It's possible that some environmental factor triggers the condition in people who are already genetically susceptible to it.
Sarcoidosis can occasionally occur in more than one family member, but there's no evidence that the condition is inherited. The condition is not infectious, so it cannot be passed from person to person.
Who is affected
Sarcoidosis can affect people of any age, but usually starts in young adults aged between 20 and 50. It is rare in childhood.
The condition affects people from all ethnic backgrounds, but it's most common in people of African descent.
A number of different tests may be carried out to diagnose sarcoidosis, depending on which organs are affected.
If your symptoms suggest you have pulmonary sarcoidosis (sarcoidosis affecting the lungs), you may have a chest X-ray or a computerised tomography (CT) scan of your lungs to look for signs of the condition.
In some cases, doctors may want to examine the inside of your lungs using a long, thin, flexible tube with a light source and a camera at one end (endoscope) that is passed down your throat. A small sample of lung tissue may also be removed during this test so it can be studied under a microscope. This is known as a biopsy.
If doctors think you may have sarcoidosis affecting other organs – such as the skin, heart or eyes – scans or examinations of these areas will usually be carried out.
How sarcoidosis is treated
Most people with sarcoidosis do not need treatment as the condition often goes away on its own, usually within a few months or years.
Simple lifestyle changes and over-the-counter painkillers (such as paracetamol or ibuprofen) to treat any pain are often all that is needed to control any flare-ups. See living with sarcoidosis (below) for lifestyle advice.
Doctors will monitor your condition to check if it's getting any better or worse without treatment. This can be done with regular X-rays, breathing tests and blood tests.
If treatment is recommended, prednisolone corticosteroid tablets are usually used.
This medication is the most effective treatment for sarcoidosis, helping to relieve symptoms and prevent damage to affected organs by reducing inflammation and preventing scarring.
However, corticosteroid medication can cause unpleasant side effects such as weight gain and mood swings if taken in high doses. Other side effects, such as weakening of the bones (osteoporosis), can also develop if it is taken for a long time. Therefore, this medication is only used when necessary.
You may initially be given a high dose of steroid medication for a short period of time, before switching to a low dose for the months or years that follow. Your condition will be monitored during this time to see how well the treatment is working.
In some cases, taking calcium or vitamin D supplements can help reduce the risk of osteoporosis caused by long-term use of steroid medication. However, you should only take these if advised by your doctor because in some people with sarcoidosis they may increase the risk of developing complications, including kidney stones.
Alternative medications may sometimes be used if steroids are not enough or there are concerns about side effects. In these cases, a type of medication called an immunosuppressant might be recommended. These medications may help to improve your symptoms by reducing the activity of your immune system.
Living with sarcoidosis
The Sarcoidosis Charity recommends the following lifestyle measures if you have sarcoidosis:
- stop smoking, if you smoke
- avoid exposure to dust, chemicals, fumes and toxic gases
- eat a healthy balanced diet
- drink plenty of water
- get plenty of exercise and sleep
Find a sarcoidosis support group.
Symptoms of sarcoidosis may come and go, and can usually be managed with over-the-counter painkillers so they don't affect everyday life. Most people with the condition find their symptoms have disappeared within a few years of their diagnosis.
For some people with sarcoidosis, the condition slowly gets worse over time and they end up with organ damage. For example, their lungs may stop working properly, causing increasing breathlessness.
Help is available for people with severe, persistent sarcoidosis – ask your doctor for advice and visit The Sarcoidosis Charity (which has a list of support groups) or the British Lung Foundation websites.