What is a granuloma?

A granuloma is a tiny cluster of white blood cells and other tissue. It 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 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 granuloma 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 the skin.

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

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

Pyogenic granuloma

Is a harmless growth of blood vessels on the 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 you should see your doctor to ensure it is not skin cancer.

What causes granulomas?

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

A granuloma is the body's way of:

• containing a bacterial, viral or fungal infection, to keep it from spreading (also called a caseating granuloma);
• isolating irritants or foreign objects (also called a non-caseating granuloma)

Granulomas caused by other conditions

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 the body
• chronic granulomatous disease — an inherited immunodeficiency condition that starts in childhood and leads to recurring bacterial and fungal infections
• Crohn's disease and inflammatory bowel disease
• rheumatoid arthritis

How are granulomas diagnosed?

Your doctor or specialist will take a medical history and examine you if they suspect you have granulomas. They may ask for tests such as a blood test, x-rays or CT scans, genetic tests or a needle biopsy.

With skin granulomas, your doctor may only need to do a physical examination to confirm a diagnosis. Occasionally, a skin biopsy may be needed.

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

How are granulomas treated?

Some people with a granuloma need treatment, but others may not. It depends on the type of granuloma.

Chronic granulomatous disease

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

Find out more about chronic granulomatous disease treatment.

Sarcoidosis

More than 1 in 2 people affected by sarcoidosis recover without treatment within 3 years. Learn more about sarcoidosis treatment.

Granuloma annulare

Most forms of granuloma annulare get better without treatment. Sometimes people may want treatment for cosmetic reasons and may be given corticosteroids or phototherapy. Find out more about granuloma annulare treatment.

Pyogenic granuloma

Generally, pyogenic granuloma will not disappear without treatment. The most common form of treatment involves surgically scraping off the granuloma and sealing the bleeding. Learn more about pyogenic granuloma treatment.

Are granulomas cancerous?

Although granulomas may appear cancerous, they are not — they are benign.

Occasionally, however, granulomas are found in people who also have particular cancers, such as skin lymphomas. So it’s important to see a doctor if you notice persistent lumps on your skin or have other symptoms of illness.

Resources and support

Find out more about skin conditions at the Australian College of Dermatologists’ community page.

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 24 hours a day, 7 days a week.