A granuloma is a cluster of white blood cells and other tissues. They tend to develop in the lungs, on the head, or on the skin. Granulomas are not cancerous.
This article will explain what a granuloma is, how and why they develop, and how to treat them. It will also advise people on when it might be a good idea to talk with a doctor.
What is a Granuloma?
A granuloma is a little lump, or nodule. It is a clump of immune cells or white blood cells.
Granulomas can be part of the immune system’s response to:
- foreign objects
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.
Granulomas are not cancerous.
There are different types of granulomas. They include:
Foreign body granulomas
When something penetrates the skin, eye, or other parts of the body, it can lead to a foreign body granuloma. This looks like a little lump at the site of the damage.
Things that can lead to foreign body granulomas include:
irritating substances, such as silica or some tattoo inks
injections, such as steroids, collagen, or vaccines
There are a few different types of skin granulomas.
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:
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. It tends to affect children more than adults, and it does not hurt.
Subcutaneous granuloma annulare usually appear on: