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What are Granulomas? Your Questions Answered

what are granulomas

It isn’t uncommon for our bodies to be exposed to circumstances that can cause uncomfortable effects in the body. Granulomas, for example, tend to be harmless, but they can be a bit of a shock if your doctor finds one that you weren’t expecting. But, wait, what are granulomas in the first place?

A granuloma is a small area of inflammation, a cluster of white blood cells that form when the body’s immune system responds to infection, inflammation, foreign objects, or irritants. Granulomas usually develop in the lungs, head, or skin, and most of the time, they are not cancerous. 

White blood cells respond to potential threats by isolating foreign objects before they do further damage, and they contain the infection so it doesn’t spread to other parts of the body. This cluster of white blood cells develops into granulomas. 

What Causes a Granuloma?  

Granulomas are not cancerous, and people without symptoms rarely require treatment. Doctors usually find granulomas when examining the body for other health issues, and they may look malignant on imaging tests, but as we’ve said, they’re generally not cancerous. 

Granulomas are soft when they first form, but they become hard over time.

So, what causes a granuloma?  


This is a non-infectious autoimmune disease that causes the formation of granulomas; it affects the lungs and other organs like lymph nodes, eyes, and skin.

In about 90% of cases, granulomas develop in the lungs. According to the Foundation for Sarcoidosis Research, when too many lumps form, they can interfere with the structure and function of an organ, and if left unchecked, it can lead to fibrosis. It has no cure, but you can manage it. 

Doctors are not sure of the exact cause of sarcoidosis, but some people stand a higher risk of developing them. These people are:

  • Those aged between 20 – 40 years
  • African Americans
  • Europeans, particularly those of Scandinavian ancestry 

Crohn’s Disease

This is an autoimmune disease that causes inflammation in the gastrointestinal tract. Symptoms include pain, rectal bleeding, and diarrhea. People who have a parent, child, or sibling with Crohn’s disease and people of Eastern European descent are more likely to suffer Crohn’s disease.  

Rheumatoid Arthritis

RA is an autoimmune condition that causes inflammation in the lining of joints and results in red, swollen, warm, and painful joints. Rheumatoid arthritis can also affect other body parts like the eyes, lungs, blood vessels, skin, and heart. Symptoms include pain in the joints, stiffness, and fatigue.  


Tuberculosis is the result of Mycobacterium tuberculosis, a bacterium that attacks the lungs. Granulomas form in response to this bacterium to contain its spread and stop its growth. 

However, they can allow the bacteria to live on in the body and spread later. Symptoms of Tuberculosis include pain in the chest, difficulty breathing, cough, swollen lymph nodes, loss of appetite, fatigue, and others.  


A fungus found in bird and bat droppings cause histoplasmosis, and lung infection occurs when you breathe in the fungus. In response to this infection, granulomas will form to stop the fungus spread. 

Most people with histoplasmosis don’t show symptoms, but it can cause serious health issues in those with weak immune systems. Symptoms include headache, body ache, cough, fever, chills, chest pain, and fatigue.  

Granulomatosis With Polyangiitis

This is a rare condition that causes inflammation in the lungs, blood vessels, and other body parts. It slows down the supply of blood to organs, causing those organs’ tissues to form granulomas, which can impair the function of the organs. 

Symptoms include joint pain, weakness, cold symptoms, and fatigue. 

Types of Granulomas

Granulomas are of different types, just as their causes vary. They are foreign body granulomas, internal granulomas, and skin granulomas. Let’s briefly discuss them below. 

Foreign Body Granulomas

As the name implies, foreign body granulomas is a type of granuloma that forms when the body reacts to an irritant or foreign body that penetrates the skin, eyes, or any other part of the body. The granuloma can look like a lump at the site where the foreign body entered the body. 

Any of the following can cause a foreign body granuloma:

  • Spider bites
  • Bee stings
  • Splinters  
  • Surgical stitches  
  • Injections  
  • Tattoo ink 

Internal Granuloma 

This type of granuloma develops inside the body and can affect the blood vessels, lungs, and gut. Internal granuloma has links to autoimmune diseases such as sarcoidosis, Crohn’s disease, and rheumatoid arthritis.  

Skin Granuloma

There are different types of skin granulomas, and they include the following.

  • Granuloma annulare: This is the most common type of skin granuloma; it is a harmless condition that causes lumps on the skin. The lumps usually appear on bony areas like fingers, elbows, legs, feet, and hands and may be shaped like a ring. The lumps may only appear on one part of the body—called a localized granuloma. When the lumps appear on more than one part of the body, it is called generalized or disseminated granuloma annulare.
  • Perforating Granuloma annulare: This granuloma causes bumps with a distinctive yellow center. The bumps often leak a clear liquid before they crust over. Sometimes, the bumps can join together and form a larger lesion. This type of skin granuloma can leave a scar.
  • Linear Granuloma: This type of granuloma is very rare. It causes bumps to develop in a line on the fingers.
  • Subcutaneous Granuloma annulare: This type of granuloma causes one bump under the skin, and it most commonly occurs in children. The bump does not hurt, and it usually appears on the scalp, legs, and arms. 

How are Granulomas Diagnosed?

what are granulomas

Diagnosis depends on where the granulomas develop. For skin granuloma, doctors only need a physical examination; they will ask questions to determine when the lumps appeared.

For internal granulomas, doctors will need to determine the underlying cause. They will ask questions about your medical history and recommend tests such as blood tests, genetic tests, imaging tests, or a biopsy. 

Treatment of Granulomas

Granulomas are usually harmless and tend to resolve by themselves over time. If there are no symptoms, treatment or follow-up imaging tests won’t be required. If treatment is needed, doctors will focus on treating the underlying cause of the granuloma.

People with skin granuloma may want to get treatment for cosmetic reasons, and in such cases, they may use corticosteroids and phototherapy. 

How Craft Body Scan Can Help Detect Granulomas

In this post, we answered the question, “what are granulomas?.” We also discussed the causes, types, and diagnosis of gallstones. As mentioned, granulomas are not cancerous and they rarely require treatment.

At Craft Body Scan, we don’t conduct granuloma scans, but we run various scans such as lung scans, heart scans, and full-body scans. Our scans can detect any abnormalities in the body and produce imaging that your doctor can analyze to diagnose granulomas. Remember that body scans are a big part of preventive medicine, and prevention is better than cure.

Click the button below to book a scan with us today.

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