What is a granuloma?

A granuloma is a tiny cluster of white blood cells and other tissue. They can appear in your lungs, skin or other parts of your body.

Granulomas aren't cancerous. They form as a reaction to infections, inflammation, irritants or foreign objects.

What are the symptoms of granulomas?

Granulomas often don't cause symptoms.

Skin granulomas may look like a rash or bumps on your skin. Sometimes they may be painful. You may have a granuloma that bleeds.

What are the types of granulomas?

Foreign body granulomas

This type of granuloma develops when your body's immune system reacts to an object or irritant that penetrates your skin or eye. They can form in reaction to:

• foreign objects such as splinters
• bee stings and spider bites
• substances that irritate you, including red tattoo ink and the silica in talcum powder
• injections, including corticosteroids and dermal fillers, such as collagen
• surgical stitches

Skin granulomas

There are several types of granulomas that can affect your skin.

Granuloma annulare (most common type)

This is a harmless skin condition that causes raised pink or flesh-coloured bumps under your skin.

The bumps are usually found in bony areas, like your elbow, and may have a distinctive ring shape.

It often affects your hands and arms, but can also affect your legs, feet, trunk or face.

Pyogenic granuloma

This is a harmless growth of blood vessels on your skin, which is fast-growing.

It appears as a nodule (lump) that often bleeds.

If you have a fast-growing lump on your skin that bleeds, see your doctor to make sure you do not have skin cancer.

What causes granulomas?

Granulomas form when your immune cells clump together and create tiny nodules at the site of the infection or inflammation.

A granuloma is your body's way of:

• stopping an infection spreading in your body (also called a caseating granuloma)
• isolating foreign objects (also called a non-caseating granuloma)

Granulomas can be part of conditions such as:

• sarcoidosis — a non-infectious disease that can cause multiple granulomas in the lungs and other parts of your body
• chronic granulomatous disease — a genetic condition that weakens the immune system. It starts in childhood and leads to recurring infections.
• Crohn's disease and inflammatory bowel disease
• rheumatoid arthritis

When should I see my doctor?

You should see your doctor if you have lumps or areas of raised skin that do not go away after a few weeks.

How are granulomas diagnosed?

Your doctor will ask you about your medical history and examine you.

With skin granulomas, your doctor may only need to examine you to confirm a diagnosis. Sometimes, a skin biopsy may be needed.

Scans may show tiny granulomas in an organ such as your lungs. These can help diagnose the cause of your granulomas.

How are granulomas treated?

Your treatment will depend on the type of granuloma you have.

Chronic granulomatous disease

You may be given antibiotics and other treatments to prevent further infections.

Sarcoidosis

More than 1 in 2 people affected by sarcoidosis recover without treatment. You may be given corticosteroid cream if you need treatment.

Granuloma annulare

Most forms of granuloma annulare get better without treatment.

If you want treatment for cosmetic reasons, you may be given:

• corticosteroids
• phototherapy (light therapy)
• cryotherapy (where your skin is frozen off)

Pyogenic granuloma

Generally, pyogenic granulomas won't go away without treatment.

The most usual form of treatment is a cream that you put on your skin. Some granulomas may need to be surgically removed.

What are the complications of granulomas?

Granuloma annulare can form ulcers. These may leave a scar.

Are granulomas cancerous?

Although granulomas may look concerning, they are not cancer — they are benign.

Occasionally, granulomas are found in people who also have certain cancers, such as skin lymphomas. So, it's important to see a doctor if you have lumps on your skin that don't go away.

Can granulomas be prevented?

Granulomas can't be prevented. They're a natural part of your body's immune defence.

Resources and support

The Australian College of Dermatologists has more information about skin conditions.

Lung Foundation Australia has information about sarcoidosis treatment.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.