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Fibrinoid Necrosis

Medically Reviewed.Last updated on 09/28/2026.

Fibrinoid necrosis occurs when certain conditions damage the inside lining of your blood vessels. It happens when conditions such as severe high blood pressure or autoimmune disorders trigger inflammation that kills the cells that line your blood vessels. Symptoms include blood in your pee or poop or swelling and pain in your joints.

What Is Fibrinoid Necrosis?

Fibrinoid necrosis happens when certain conditions damage the inner lining of your blood vessels. “Necrosis” is the medical word for cell death. “Fibrinoid” refers to substances like fibrin that attach to the inside of your blood vessels.

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Some autoimmune diseases or infections may deposit fibrin and other substances in your blood vessel walls. The substances cause inflammation that kills cells in the blood vessel wall. Damage to your blood vessels may make you bleed more than usual or cause internal bleeding. Severe blood vessel damage may lead to organ failure.

Symptoms and Causes

Symptoms of fibrinoid necrosis

This disease damages your blood vessels so you have unusual or excessive bleeding. Symptoms include:

  • Bleeding gums
  • Blood in your pee or poop
  • Fever
  • Joint pain and swelling
  • Nosebleeds
  • Rash that makes your skin look red or purple (depending on your skin tone)
  • Weakness from internal bleeding

Without treatment, fibrinoid necrosis can affect blood flow to your organs and cause organ failure.

Fibrinoid necrosis causes

Anything that damages your blood vessels can lead to fibrinoid necrosis. Common causes include:

  • Autoimmune diseases: Some types of vasculitis and other autoimmune diseases may cause inflammation that leads to fibrinoid necrosis.
  • Bacterial endocarditis: This is an infection in your heart that blocks small blood vessels in your heart muscle.
  • Preeclampsia: Women with this condition may develop high blood pressure.
  • Severe high blood pressure: This can affect blood vessels in your brain, heart, kidneys and other organs.
  • Vasculitis: Diseases such as polyarteritis nodosa and IgA vasculitis can cause inflammation in your blood vessels.

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Diagnosis and Tests

How doctors diagnose fibrinoid necrosis

A healthcare provider will ask about your symptoms and health history. They may ask if you have certain conditions that lead to this disease. They’ll also do a physical exam. And they may take tissue samples to check your blood vessels for damage and fibrin deposits.

Management and Treatment

How is fibrinoid necrosis treated?

Treatment involves managing inflammation and the underlying conditions that cause this disease. For example, providers may prescribe:

  • Antibiotics: This is a treatment for bacterial endocarditis.
  • Blood pressure medication: You may receive medications like ACE inhibitors or calcium channel blockers if high blood pressure causes fibrinoid necrosis.
  • Corticosteroids: This medication reduces inflammation from vasculitis.

Can fibrinoid necrosis be reversed?

No, because there’s no way to reverse cell death. But treatment to manage the underlying condition will prevent more cell death.

When should I see my healthcare provider?

Any unusual bleeding, like spotting blood in the toilet when you pee, is a reason to talk to a healthcare provider. That’s especially true if you have conditions like autoimmune diseases or very high blood pressure that can cause fibrinoid necrosis.

Outlook / Prognosis

What can I expect if I have fibrinoid necrosis?

That depends on your situation. Treatment for the condition that causes fibrinoid necrosis may help with symptoms and keep it from getting worse. The prognosis may be different if you have a severe form of fibroid necrosis. Your healthcare provider will explain what you can expect in your specific situation.

Prevention

Can fibrinoid necrosis be prevented?

The only way to prevent this disease is to manage the underlying condition. If that’s your situation, follow your treatment plan and let your healthcare provider know about any changes, like new symptoms or ones that get worse.

A note from Cleveland Clinic

Fibrinoid necrosis may be a sign that you have an underlying condition, like an autoimmune disorder or high blood pressure. These conditions can trigger a medical chain reaction that kills cells that line your blood vessel walls. Unusual bleeding may be your first clue. That’s the sort of change in your body that you should discuss with a healthcare provider. Getting treatment for the underlying condition will help with fibrinoid necrosis symptoms.

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Medically Reviewed.Last updated on 09/28/2026.

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References

Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

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