Cryptogenic Organizing Pneumonia (COP)

Last Updated 11/02/2020

Author:Roberto Carbone, MD, FCCP

About Cryptogenic Organizing Pneumonia (COP)

Cryptogenic organizing pneumonia (COP) is a lung condition that affects the small airways, or bronchioles, and tiny air sacs, or alveoli, in your lungs. The cause of COP is unknown.

You may have heard COP called bronchiolitis obliterans with organizing pneumonia. This name is no longer used.

Key facts about COP
  • COP is a form of organizing pneumonia.
  • Although pneumonia is in the name, COP is not an infection.
  • The term cryptogenic in the name means that no specific cause is known.
  • The most common symptoms of COP include:
    • Shortness of breath; and
    • Dry cough.
  • COP is typically treated with oral (by mouth) steroid medications.

How COP affects your body

Symptoms can begin gradually, over a few weeks to months. COP often seems like a flu-like illness. Most people show symptoms such as:

If the disease continues, shortness of breath can happen even when you’re at rest. Rarely, you may have:

  • Chest pain;
  • Joint pain;
  • Night sweats; and
  • Coughing up blood.
How serious is COP?

COP can cause severe lung damage. It may require you to stay in the hospital for treatment.

Those who are treated usually show improvement.

People with COP should be monitored. It is common for COP to come back after treatment.

Most people recover after weeks or months with steroid treatment, such as prednisone.

Symptoms of COP

The most common symptoms are:

  • Long-term (2 to 4 months), dry cough;
  • Low-grade fever;
  • General feeling of not being well (malaise);
  • Shortness of breath;
  • Loss of appetite; and
  • Weight loss.

What are risk factors for COP?

The cause of COP is unknown. Both men and women are affected. The average age at COP diagnosis is 50 to 60 years. A condition similar to COP may occur as a side effect of certain medications.

Diagnosing COP

COP is a rare disease. Its cause is unknown. It is usually diagnosed by ruling out other diseases. Sometimes, the signs, symptoms, imaging, and biopsy results of COP may be a side effects of certain medications. Your health care provider can determine whether your symptoms are caused by a medication. Stopping that medication will help treat the disease.

When should you see your health care provider?

Contact your health care provider if you have:

  •  A long-lasting (2 to 4 months), dry cough; or
  • Shortness of breath that does not go away.

The faster you get treatment, the faster you will improve. This is especially true for:

  • Young people;
  • People older than 65 years of age; and
  • Anyone with other long-term (chronic) health problems, such as asthma.

How COP is diagnosed

Your health care provider will ask you many questions about your health to put together a detailed medical history. There will likely be several tests before your health care provider gives you a diagnosis.

A diagnosis is usually made after:

  • A physical evaluation;
  • A detailed medical history; and
  • Identification of typical symptoms or test results.

Your health care provider may also order specialized tests, such as:

Treating COP

Sometimes, COP goes away on its own. In most cases, some treatment is required. Your health care provider will likely prescribe corticosteroid medications, such as prednisone. Cytotoxic drugs, such as cyclophosphamide, may be used to treat COP when corticosteroids do not help.

Note: COP does not respond to antibiotics.

Managing COP

Most people with COP will need treatment. Usually, treatment will be a steroid medication. You will likely see improvement within a few days or weeks. In some cases, COP may recur as you take less medication. That means you may start to see symptoms again. If this happens, you will need another treatment.

In some people, the disease may progress despite treatment.

People with COP typically recover fully. It is important that you take any medications as your health care provider tells you. Your provider may suggest a flu vaccine and pneumococcal vaccine every year.

You may need follow-up testing.


The American Lung Association’s Living with Lung Disease support community connects patients and caregivers with others facing this disease. You can also call the Lung HelpLine at 1-800-LUNGUSA. A trained professional can answer your questions and connect you with support.

Questions to ask your health care provider

Making notes before your visit and taking along a trusted family member or friend can help you through the first appointment with your provider. Questions to ask your health care provider include:

  • Do I have COP?
  • What tests will I need?
  • What are the symptoms?
  • Does COP only affect my lungs?
  • What is the treatment?
  • Is it necessary to be admitted to the hospital, or can I be treated at home?
  • What is the chance of relapse?
  • Are there alternative treatments if the first one does not work?
  • Could there be any complications from COP or its treatment?