What is Blau syndrome?
Blau syndrome is a very rare inflammatory condition. It affects the immune system and can cause problems in different parts of the body.
Only about 200 cases have been reported worldwide. However, it is likely underdiagnosed, so more people may have it than we know.
Current estimates suggest it affects about 1 in 2 million people.
Blau syndrome mainly affects:
- the skin
- the joints
- the eyes
Getting the right diagnosis early is very important. Early treatment can help prevent:
- long-term joint damage
- loss of vision
Who can get Blau syndrome?
Blau syndrome usually starts in young children, often before age 5. However, it can also be diagnosed later in life.
It is a genetic condition, which means it can run in families.
- If one parent has Blau syndrome, there is a 50% chance their child will inherit it.
- It affects people of all genders and ethnic backgrounds.
You may also hear other medical names, such as:
- juvenile systemic granulomatosis
- early-onset sarcoidosis
These are medical terms for similar conditions.
Blau syndrome has three main symptoms. Doctors often call this a “triad”.
1. Skin changes
- A rash or small lumps under the skin
- Skin may look red or inflamed
2. Joint problems (arthritis)
- Swelling
- Pain
- Stiffness, especially in the hands, wrists, knees, or ankles
3. Eye inflammation (uveitis)
- Red or painful eyes
- Sensitivity to light
- Blurred vision
Eye inflammation is serious and can lead to vision loss if not treated.
Other possible symptoms
Some people may also have:
- Fever
- Tiredness (fatigue)
- Feeling generally unwell
Blau syndrome is caused by a change (variant) in a gene called NOD2.
Genes are instructions in your body that tell it how to work.
- The NOD2 gene helps control part of the immune system
- Changes in this gene can cause the immune system to become overactive
- This leads to inflammation and the formation of small lumps called granulomas
You only need one copy of the changed gene to develop the condition.
Blau syndrome can be diagnosed through a genetic test.
Before testing, doctors may:
- review symptoms
- rule out infections (like tuberculosis)
- rule out other conditions (like juvenile arthritis)
You may see specialists such as:
- a paediatrician (children’s doctor)
- a rheumatologist (joint and immune system specialist)
Early diagnosis is important to start treatment as soon as possible.
There is no cure, but treatment can control symptoms and prevent damage.
Common treatments include:
Biologic medicines
- These target inflammation in the body
- Examples include:
- adalimumab
- infliximab
Other medicines
- Corticosteroids (for short-term use)
- Methotrexate
- Other targeted therapies in some cases
Pain relief
- Anti-inflammatory medicines like:
- ibuprofen
- naproxen
Treatment plans are tailored to each person and managed by specialists.
Blau syndrome is a serious condition, but with treatment, many people can live well.
Challenges may include:
Regular treatment
- Some medicines are given by injection or infusion
Medicines may stop working
- The body can sometimes develop resistance over time
Higher risk of infections
- Extra care is needed, especially for children
Ongoing care
- Regular check-ups with specialists are important
When should you seek medical advice?
Speak to a doctor if you or your child has:
- ongoing joint swelling or pain
- unexplained skin rashes
- eye redness or vision changes
If symptoms continue or worsen, keep following up. Early treatment makes a big difference.
Is Blau syndrome autoinflammatory or autoimmune?
Blau syndrome is an autoinflammatory condition.
This means:
- it involves the innate immune system (the body’s first line of defence)
- it is different from autoimmune diseases, which involve a more targeted immune response
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