Did you know you could be living with amyloidosis and not even know it? About half of people with localized amyloidosis don’t have any symptoms. This type of amyloidosis happens when clumps of abnormal protein called amyloid fibrils (or deposits) build up in just one part of the body, like in one organ or tissue. These clumps can damage that area and make it harder for the organ to work the way it should.

Localized amyloidosis, also called organ-limited amyloidosis, can develop in different parts of the body, like the skin, airways, or eyes. This condition affects people in different ways depending on where it shows up. Localized amyloidosis is not the same as systemic amyloidosis. In systemic amyloidosis, amyloid deposits are found in more than one organ, which can cause more serious complications. Systemic amyloidosis is much more common than the localized type.

In this article, we’ll cover some key facts about localized amyloidosis. We’ll look at how it develops, where it affects the body, who is most at risk, and how it’s diagnosed and treated.

1. Localized Amyloidosis Is Rare

Amyloidosis is a rare disease, and localized amyloidosis is even rarer. Only about 7 percent to 12 percent of all people with amyloidosis have the localized kind. Each year, around 4,000 people in the United States are diagnosed with amyloidosis. This means only 300 to 500 people a year find out they have the localized form.

Almost all cases of localized amyloidosis are a subtype called amyloid light chain amyloidosis (AL amyloidosis). Studies show that people are usually diagnosed with localized AL amyloidosis around age 59. Localized AL amyloidosis affects about the same number of men and women, according to the journal Frontiers in Oncology. However, some types of localized amyloidosis are more common in certain groups. Several studies from the American Journal of Hematology found that women are more likely to develop amyloidosis in the skin and soft tissues. People with lung localized amyloidosis are usually older when they’re diagnosed and are more likely to have smoked cigarettes.

2. Malfunctioning Immune Cells Cause Localized Amyloidosis

Scientists think that a type of white blood cell (plasma cell) may help cause localized AL amyloidosis. Plasma cells are part of the immune system. They make proteins called antibodies that find and attack harmful bacteria. Antibodies help prevent bacteria from making us sick.

In localized AL amyloidosis, some plasma cells start making misfolding antibody pieces. We call these pieces light chains. Light chains form the amyloid clumps (called amyloid fibrils) that build up and cause symptoms. Scientists still don’t know how or why light chains turn into amyloid fibrils.

3. People With Localized Amyloidosis Are More Likely To Have an Autoimmune Disease

About 7 percent to 21 percent of people with localized AL amyloidosis also have an autoimmune condition. A common one is rheumatoid arthritis, which causes joint pain and swelling. People with localized AL amyloidosis are also more likely to have plasma cell-related disorders. These include certain types of lymphomas (a type of cancer that starts in the immune system).

Scientists don’t know why these conditions develop with localized amyloidosis. One possibility is that an overactive immune system could contribute to developing amyloidosis. We need more research to understand how and why localized amyloidosis develops.

4. Localized Amyloidosis Can Affect Any Organ

Localized amyloidosis can happen anywhere in your body. However, it does affect some organs and tissues more often. The most common sites of localized amyloidosis are:

• Genitourinary tract, including the bladder and urethra (the tube urine moves down)
• Skin (called primary cutaneous localized amyloidosis)
• Upper airways and lungs, including the larynx (the hollow tube in your neck used to speak and breathe)
• Gastrointestinal (GI) tract, including the stomach, upper and lower intestines, and colon

5. Localized Amyloidosis Causes Many Different Symptoms

About half of people with localized amyloidosis don’t have any symptoms. Your healthcare team may find signs of the condition during routine scans or tests, even if you feel fine. Studies show that amyloidosis in the airways or urinary tract is most likely to cause symptoms because it can affect important body functions like breathing or urinating. People with amyloidosis in the lungs, digestive system, or skin are less likely to have symptoms.

Below, we list some common symptoms for several types of localized amyloidosis.

Genitourinary

When amyloid fibrils develop in your urethra and bladder, you may experience:

• Blood in your urine, which is caused by amyloid deposits damaging blood vessels
• Recurring urinary tract infections
• Burning sensation when urinating

Upper Airway

When amyloid fibrils build up in your larynx and lungs, you may have these symptoms:

• Hoarseness
• Difficulty swallowing
• Coughing
• Shortness of breath

Skin

Symptoms of amyloidosis in the skin include:

• Raised bumps on the skin that range in color from red to dark brown, depending on your skin tone
• Itching

Gastrointestinal Tract

When amyloid fibrils build up in your stomach and intestines, people report the following symptoms:

• Heartburn
• Constipation
• Bleeding in the gut

6. Localized Amyloidosis Is Not the Same as Systemic Amyloidosis

An important early step in diagnosing localized amyloidosis involves ruling out systemic disease. The treatments and outcomes of localized and systemic amyloidosis are different. In general, localized amyloidosis has very good outcomes. However, the systemic condition can be more difficult to treat and manage. Your healthcare team will need to know which type you have.

The only way to be sure you have localized amyloidosis is to take a tissue sample from the affected organ. This procedure is called a biopsy, and it’s performed by your healthcare team. The tissue sample is then tested for amyloid protein fibrils.

Next, your medical team will perform tests to see if you have systemic amyloidosis. These tests include:

• A bone marrow biopsy to check if the abnormal plasma cells are present throughout the body
• A biopsy
• Blood and urine tests for light-chain proteins
• Blood and urine tests for damage in other organs

7. Localized Amyloidosis Is Sometimes Curable

About half to three-quarters of people with localized amyloidosis need treatment. Your healthcare team will suggest treatment options if you’re experiencing symptoms. More than 70 percent of people feel better after the first treatment.

Localized amyloidosis is often treated by removing the affected tissue through surgery. About 60 percent to 80 percent of people with localized amyloidosis undergo surgery. Surgery can sometimes completely cure localized amyloidosis. The entire amyloid deposit and all abnormal plasma cells need to be taken out. If surgery isn’t possible, radiation therapy is another option. Radiation kills the abnormal plasma cells and reduces the buildup of amyloid fibrils.

Some treatments target specific symptoms of certain types of amyloidosis. For example, in skin amyloidosis, doctors may use:

• Corticosteroids — Also called steroids, these help reduce inflammation and itching.​
• Retinoids — These promote skin cell turnover and can improve skin appearance.

Other treatments, like laser therapy and phototherapy, may also be used to manage symptoms.

8. Localized Amyloidosis Has Very Good Outcomes

In general, the outcome expected with localized amyloidosis is very good. It’s rare to develop systemic amyloidosis. Many studies report that no or very few people go on to develop systemic disease. Localized amyloidosis may be completely cured. Some people might need follow-up treatments if the condition comes back. About 1 in 5 people will need more than one treatment. People with localized amyloidosis tend to live as long as the general population.

Talk With Others Who Understand

MyAmyloidosisTeam is the social network for people with amyloidosis and their loved ones. On MyAmyloidosisTeam, more than 2,700 members come together to ask questions, give advice, and share their stories with others who understand life with amyloidosis.

Are you living with localized amyloidosis? What area of your body is affected? Share your experiences in the comments below, or start a conversation by posting on MyAmylodosisTeam.