Sarcoidosis, also known as sarcoid, is generally described as an inflammatory condition of unknown cause which can affect various parts of the body and can occur at all ages. 

Inflammation - what does it really mean?

Inflammation is one of the ways our body has of dealing with injury, as it tries to eliminate the cause of the injury and to repair any damage that has been caused.

Inflammation is one of the basic tools our immune system has to protect and defend our bodies from bacteria, viruses and other foreign substances. When there has been major damage, inflammation helps to heal it by scarring. An example of this is the skin scar that follows a bad cut. However, the immune system can occasionally overreact and go ‘over the top’. Sometimes the immune system is triggered by something from outside, but when that ‘something’ goes away, the immune system remains switched on, and the inflammation becomes a self-maintaining process. In such a situation, inflammation, rather than being helpful and protective, can cause unnecessary damage to the body instead.

Inflammation-induced damage, when severe, is healed by scar tissue formation. Fibrosis is just the medical term for scarring and both just mean that there is permanent damage. So ‘pulmonary fibrosis’ means that there is permanent damage and scarring in the lungs.

To summarise, sarcoidosis is not a cancer and it is not an infection. The heart of the problem is that the immune system is overactive.

What is the cause of sarcoidosis?

It is still unclear what causes sarcoidosis to develop in any one individual. It seems likely that an initial 'trigger' such as infection is responsible for setting off the sequence of events that lead to the immune system overactivity characteristic of sarcoid.

It is unlikely that there is a single trigger setting off the immune system that is the same in all people with sarcoidosis. The real cause is probably that we all have immune system vulnerabilities - and by bad luck, the wrong trigger for any single person comes along. 

Sarcoidosis can occur at all ages, although most commonly in early to middle adulthood.

Which parts of the body are affected?

It can be frightening to learn that sarcoidosis can occasionally affect all parts of the body including the heart and the lungs. It is worth understanding what the usual pattern of organ involvement is in sarcoid.

The organs most commonly affected in people with sarcoidosis are the lungs and the lymph nodes (or glands), particularly those inside the chest. Other organs which can be affected, although much less frequently, include the liver, the eyes, the skin, the glands that produce tears and the salivary glands. Rarely, sarcoidosis can involve the heart or the brain (less than 1 in 20 of patients). 

Understanding the disease

Sarcoidosis is frequently a mild and self-limiting disease. Beware of medical text books and the internet. Both contain much true information but often they tend to focus on the most severe types of sarcoidosis. People seeking information often come away with the wrong impression that all sarcoidosis is severe and life-threatening, but this is definitely not the case.

  • We now know from X-ray surveys that many people have had sarcoidosis without ever knowing that they have had it. The chances are that this scenario does not apply to you (or you would not be reading this page!).
  • What may well apply to you is the fact that, more often than not, sarcoidosis goes away, sometimes without treatment, within three years. Often, when the lungs have been involved, chest X-rays will show permanent abnormalities which represent scar tissue (an after-effect of active disease), but provided that the activity of the illness has gone away, these chest X-ray abnormalities do not progress and do not have an effect on either the quality or length of an individual's life.
  • In a small minority of individuals, sarcoidosis smoulders on, sometimes with dangerous organ involvement. In about 2-5% of sufferers, life expectancy may be shortened. However, appropriate treatment minimises shortening of life and in some cases can prevent the development of life-threatening disease.
  • In general, sarcoidosis tends to remain much the same in its pattern in any single person. In other words, in more severe disease, it does not tend to move around the body, from organ to organ (e.g. from the brain to the heart to the lungs). In most cases, an individual pattern becomes obvious at an early stage in the disease and it is then a question of focusing on your individual pattern of disease. Serious involvement of the heart and the brain are really quite rare, despite what you might read on the internet.
  • When you are diagnosed with sarcoid you will undergo some tests to see if there is hidden organ involvement. Symptoms which affect quality of life and organ involvement do not always correlate. You would think, on common-sense grounds, that feeling ill goes with dangerous disease. This is not so. With this disease you can feel fine but be at danger, and you can feel unwell without being at danger.
  • A major issue for many people with sarcoidosis is loss of quality of life. The most common set of symptoms are tiredness and joint pains. Night sweats, fevers and weight loss are also common. These symptoms do not refer to a particular organ involvement, and are caused by the inflammation, but can have a massive impact on your quality of life. In particular, fatigue tends to be the most troublesome symptom. When it does occur, it can be particularly frustrating, as other people are not aware of it and it can be difficult to convey how you feel. Often, for this reason, people with sarcoidosis can feel alone or feel that they are imagining this debilitating symptom.

What are the main side effects of steroids?

Side effects vary widely according to the dose used and duration of treatment.

In the short term, the most common side effects of steroids are:

  • increased appetite and weight gain. The weight will tend to reverse once steroids are stopped or reduced, although a diet may be needed in some cases.
  • indigestion and heartburn. Taking steroids after a meal may help prevent this.
  • difficulty sleeping. This may be reduced by taking steroids in the morning.
  • changes in mood, irritability.

In the longer term, steroids can cause:

  • raised blood sugar levels. A family history of diabetes makes this more likely.
  • osteoporosis, a reduction in the bone’s density, making the bones weaker
  • raised blood pressure
  • eye problems such as cataracts or, rarely, glaucoma

The side effects of steroids vary dramatically according to the dose used in the long term. High dose and low dose steroids can essentially be considered as two different drugs. Long-term treatment with low dose steroids (i.e. doses less or equal to 10 mg once daily) can be considered to be a very mild treatment, especially as these doses are very similar to the body’s natural levels of steroids. Low dose steroid treatment is usually associated with very few, if any, side effects.

Should I change my diet?

Specific changes to the diet are only needed if levels of calcium are high either in the blood (<10% of patients) or in the urine (30% of patients). In these cases, a diet poor in calcium (less milk and dairy products) may be recommended. Apart from this, no specific recommendations are needed, except the general advice to follow a healthy diet with plenty of fruits and vegetables.

Can I take vitamins and supplements?

You should avoid taking vitamin D, as this vitamin is produced in excess by sarcoid granulomas. Unless osteoporosis is present, we normally recommend also avoiding calcium supplements, although this can be discussed on a case-by-case basis.

What can I do about the tiredness/fatigue?

Tiredness and lethargy are extremely common in sarcoidosis, and in some people may last for considerable periods of time. Significant tiredness may be difficult to treat and can significantly affect quality of life. Low dose steroids can be helpful in some individuals. Others find regular exercise helps in overcoming tiredness. Often patients find they need to sleep longer hours, and may need short periods of rest during the day. Reducing or tailoring commitments to the level of fatigue may be required while the disease is active.

Sarcoidosis tests

A diagnosis of sarcoidosis is usually reached by putting together the results from a number of different tests, which can include chest X-rays and CTs, bronchoscopies and biopsies.

ECG Holter monitor

This test monitors your heart rhythm over 24, 48 or 72 hours, or five or seven days. The monitor is about the size of a mobile phone and you will need to wear it around your waist or carry it in your ...

Lung function tests

We have a number of tests that we use to look at lung function, and how your lungs are functioning in aspects of your breathing and exercise. 


A bronchoscopy is a procedure where a doctor can look at the trachea (windpipe), the bronchi (branches of the airways) and into some areas of the lungs.

PETCT sarcoidosis scan

A PET-CT scan combines a PET and a CT scan, and by combining these two techniques, we are able to provide important information to help your doctor design the best treatment plan for you.

Sarcoidosis treatment

Many patients with sarcoidosis do not need treatment. When treatment is considered, steroids are the first choice, unless there is a reason they can’t be used.

We have more information available about our cardiac sarcoidosis clinic, including what to expect, how the referral system works and how to contact the team. 

Experts in cardiac sarcoidosis

Professor Athol Wells
Head of the ILD unit

Dr Rakesh Sharma
Clinical lead for heart failure

Dr Paul Oldershaw 
Consultant in cardiology

Dr Sanjay Prasad
Clinical lead in the CMR unit

Dr Kshama Wechalekar
Consultant in nuclear medicine

Dr Vasileios Kouranos
Consultant respiratory physician

Contact details

If you are a health professional and have any questions about the condition or the referral process, please contact Vasileios Kouranos on 020 7351 8742 or via email

You can also contact the cardiac sarcoidosis clinic administrators:

Terri Cartwright 
Tel: 020 7352 8121, ext 8018  
Fax: 020 7351 8951  

Ciara Philpott
Tel:  020 7351 8164  
Fax: 020 7351 8776