A granuloma is a cluster of white blood cells and other tissues that are generally not cancerous. They tend to develop in the lungs, on the head, or on the skin.

Granulomas often go away on their own. However, treating underlying health conditions can also help clear them.

A granuloma is a small lump or nodule consisting of white blood cells. They are not cancerous.

Granulomas can be part of the immune system’s response to:

When the cells clump together, they protect the body from potential threats in two ways. The first is keeping an infection in one place to stop it from spreading to other parts of the body. The second is isolating an irritant or foreign object so it cannot do any further damage to the body.

Sometimes, long-term conditions such as Crohn’s disease and sarcoidosis can cause granulomas.

There are three types of granulomas: foreign body granulomas, skin granulomas, and internal granulomas.

Foreign body granulomas develop when something penetrates the skin, eye, or other parts of the body, which can lead to a foreign body granuloma. This looks like a little lump at the site of the damage.

Internal granulomas develop inside the body. They can affect the lungs, gut, or blood vessels. Autoimmune diseases, or health conditions linked to the immune system, are the most common cause of internal granulomas.

There are several types of skin granulomas:

Granuloma annulare

Granuloma annulare is a skin condition that causes bumps underneath the skin. The lumps are usually pink, yellow, or flesh-colored. They usually appear in the shape of a ring. Granuloma annulare can affect any part of the body. They commonly appear on the:

  • fingers
  • hands
  • top of the feet
  • ankle
  • elbows

The lumps may appear on one part of the body only. Doctors call this localized granuloma annulare. Some people may experience lumps on more than one part of the body at a time. Doctors call this generalized or disseminated granuloma annulare.

Subcutaneous granuloma annulare

Subcutaneous granuloma annulare is often just one lump underneath the skin.

Although they can appear anywhere on the body, subcutaneous granuloma annulare usually appears on:

  • fingers
  • hands
  • feet
  • forehead
  • neck
  • abdomen

Perforating granuloma annulare

Perforating granuloma annulare causes lumps that develop a yellow center. People will often find a clear liquid leaking from the lumps before they crust over. The lumps can also join together to create a larger lesion.

Perforating granuloma annulare can leave a scar.

Linear granuloma

Linear granuloma is rare, particularly in adults. The lumps tend to develop in a line or broad band-like papules.

Granulomas develop when the body sees something as a threat, such as a foreign object or an infection.

Macrophages, a type of immune cell, reach the area and attempt to fight off the infection or foreign object. If they are unable to do so easily, they cluster around the problem and become surrounded by another type of immune cell called lymphocytes.

Infectious causes include:

  • tuberculosis
  • parasites, such as Schistosomiasis
  • fungi, including Aspergillus

Non-infectious causes include:

  • autoimmune conditions, such as sarcoidosis
  • cancer
  • foreign materials, such as:
    • splinters
    • irritating substances, such as silica or some tattoo inks
    • injections, such as steroids, collagen, or vaccines
    • stitches

The following outlines conditions that have a strong association with granuloma development.

Tuberculoisis

People with tuberculosis, for example, will often have granulomas inside their lungs. This is the immune system’s way of stopping the Mycobacterium tuberculosis bacteria from spreading to other parts of the body.

Sarcoidosis

Sarcoidosis is an autoimmune condition. It develops when groups of cells in the immune system form granulomas.

Although the exact cause of the granulomas is unknown, researchers suspect they develop as a result of an infection. In 95% of cases, the granulomas develop in the lungs. They can also affect the skin, lymph nodes, eyes, and liver.

According to the Foundation for Sarcoidosis Research, having too many granulomas can interfere with the structure and function of organs and lead to fibrosis, which is permanent scarring.

Crohn’s disease

Crohn’s is also an autoimmune condition. It causes inflammation in the gastrointestinal tract, leading to a variety of symptoms, including:

  • pain
  • diarrhea and cramping
  • feeling and being sick
  • rectal bleeding

Some people with Crohn’s disease will develop granulomas in their gut.

Scientists do not know what causes Crohn’s disease. Risk factors include having a parent, child, or sibling with the condition and being of Eastern European descent. There have also been increased reports of Crohn’s disease developing in African American populations.

Granulomatosis with polyangiitis

Granulomatosis with polyangiitis is a rare disease.

It is a type of vasculitis, or inflammation in the blood vessels. Doctors used to call it Wegener’s granulomatosis. Granulomas develop in the blood vessels, making it difficult for blood to reach vital organs.

Common symptoms include:

  • joint pain
  • weakness and fatigue (lack of energy)
  • ongoing cold symptoms, such as a runny nose

Diagnosis will depend on where the granulomas are.

Doctors will usually only need to do a physical examination to diagnose skin granulomas. In most cases, they will also ask a few questions about the lumps, such as when they appeared.

To diagnose internal granulomas, doctors will need to understand the underlying cause of the problem. To do this, they may:

  • ask a series of questions about the person’s symptoms
  • carry out a blood test
  • carry out an imaging test, such as an X-ray or CT scan
  • carry out a genetic test
  • take a tissue sample by performing a needle biopsy

Treatment will depend on the underlying cause of the granuloma. Skin granulomas will often resolve without treatment within 2 years.

Possible treatments for small, localized skin granulomas include:

  • applying liquid nitrogen
  • applying steroid creams
  • getting steroid injections

If the granulomas are more widespread, a doctor may prescribe medications, such as:

  • dapsone
  • retinoids
  • niacinamide

Granulomas can be caused by underlying health conditions, so treatment can also focus on treating the underlying cause. A person can speak with a doctor to find out which treatment options are most appropriate for them.

Anyone with a granuloma that does not get better on its own or that keeps coming back should speak with a doctor.

People who feel they may have an underlying autoimmune disorder should also seek medical attention.

No, granulomas are not cancerous.

Granulomas can form anywhere on the body. Depending on the type of granuloma, they can develop on the:

  • fingers
  • hands
  • top of the feet
  • ankle
  • elbows
  • forehead
  • abdomen
  • neck

They can also develop on the inside of the body, including the lungs and lymph nodes.

    Granulomas are typically harmless. However, some, such as foreign body granulomas, can cause:

    • scarring
    • keloid scar formation
    • ulcers
    • abscesses

    The underlying cause of granulomas, such as tuberculosis, Crohn’s disease, and sarcoidosis, can cause additional complications.

    Granulomas grow as a result of infection or foreign body. They can also grow as a result of an underlying health conditions, such as sarcoidosis and Crohn’s disease.

    Granulomas are small clumps of immune cells. They are usually a normal part of the body’s immune system, working to isolate threats from the rest of the body. Granulomas are not cancerous.

    They can develop anywhere on the body, including the skin, lungs, and other organs, and they tend to disappear on their own.

    Granulomas can develop without reason if someone has an autoimmune condition, such as Crohn’s disease or sarcoidosis.

    Sometimes, they can damage the body and lead to scarring. When this is the case, doctors will usually recommend treating the underlying condition.