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Condition confusion: Why IgG4-RD is often misdiagnosed

Last updated June 2, 2025, by Agata Boxe
✅ Fact-checked by Patrícia Silva, PhD

Diagnosis challenges
Common misdiagnoses
Testing
Second opinions
Accuracy
IgG4-RD specialists

 

IgG4-related disease (IgG4-RD) is often misdiagnosed because its symptoms can resemble those of cancer and other conditions. As a result, an IgG4-RD misdiagnosis can lead to treatments or procedures that aren’t needed.

If you suspect you may have IgG4-RD, there are ways to get closer to a diagnosis. Knowing how to advocate for yourself and ask the right questions can help you get the care you need.

Why IgG4-RD is hard to diagnose

IgG4-RD can be challenging to diagnose as its symptoms overlap with those of other diseases, and there is no single, definitive diagnostic test for the condition.

It is more common in men and tends to affect multiple organs. One of the most commonly impacted sites is the pancreas, where the condition often manifests as chronic pancreatitis.

Doctors describe IgG4-RD as a kind of insidiously progressive disease, or a condition that tends to worsen over time but does not involve immediate or obvious symptoms. You may not realize for months or years that you have it until you’ve begun experiencing visible symptoms. Such symptoms may include:

  • a mass resembling cancer
  • fatigue
  • headaches
  • unexplained weight loss
  • bulging eyes
  • bulges on the face
  • thyroid problems
  • breathing issues
  • urinary problems
  • enlarged kidneys
  • abdominal pain
  • yellowing of the skin or eyes.

Because the symptoms can vary widely and affect different organs and tissues, it is often challenging for doctors to determine that they are dealing with IgG4-RD and not another disease.

And like with other rare diseases, providers may not even be aware of IgG4-RD and may not consider it when assessing your symptoms.

Common misdiagnoses and overlaps

Because its symptoms are wide-ranging and nonspecific, IgG4-RD is often mistaken for conditions with symptoms similar to IgG4-RD, including:

  • amyloidosis
  • atherosclerosis
  • Erdheim-Chester disease
  • interstitial lung disease
  • sarcoidosis
  • lymphoma and cancers of the kidneys, pancreas, and bile ducts
  • primary sclerosing cholangitis
  • autoimmune diseases such as Sjögren’s syndrome and granulomatosis with polyangiitis (Wegener’s).

As a result of misdiagnosis, some people with IgG4-RD may undergo unnecessary, costly, and invasive procedures for conditions they don’t have.

An example is the Whipple procedure, which involves removing the head of the pancreas and sections of other organs to treat tumors and other problems with the pancreas, small intestine, and bile ducts.

The importance of thorough testing

Thorough IgG4-RD testing is vital for correctly diagnosing IgG4-RD and differentiating it from other diseases.

IgG4-RD tests usually are a combination of:

  • IgG4 serum level testing, which assesses the levels of the antibody IgG4
  • imaging of specific organs that examines their potential enlargement
  • biopsy, which involves collecting and analyzing a tissue sample.

While serum IgG4 levels are often elevated in IgG4-RD, this is not true for all cases. In fact, 20% to 30% of people with the disease can have normal serum IgG4 levels.

Biopsy results can also be misleading on their own. For example, some sites, such as the lymph nodes, are less likely to have findings indicative of the disease. Further, with long-standing disease, the typical features of IgG4-RD may not be identified through this type of test.

Due to each testing type’s limitations, a more comprehensive approach using multiple diagnostic techniques is typically necessary to diagnose IgG4-RD.

What to do if you suspect a misdiagnosis

If you have concerns about the accuracy of your diagnosis, bring them up to your doctor. You have the right to expect them to take you seriously.

You can ask your provider if you have been tested you for IgG4-RD. If you haven’t, you can request such testing.

Also, you can seek a second opinion, ideally from a healthcare professional specializing in IgG4-RD diagnosis and treatment. An expert can take another look at any previous tests you may have undergone, and reassess the results, or recommend new or additional testing.

Meanwhile, do document all your symptoms and any treatments you may be receiving. Keep this information for your records and share it with your providers.

Advocating for a clear diagnosis

For people living with rare diseases, including IgG4-RD, obtaining a clear diagnosis is often challenging. Doctors may not be familiar with these conditions and may not know how to diagnose or treat them.

To advocate for a clear, accurate diagnosis, prepare for a discussion with your health provider. If you believe you may have IgG4-RD, try to learn as much as possible about its symptoms, diagnosis, and treatment.

Think beforehand about what you want to say and write it down. Bring your notes with you to your appointment, and, if it helps, bring a friend or loved one with you who can help advocate for your health.

The importance of IgG4-RD specialists

Finding an IgG4-RD specialist is essential if you suspect you may have the disease. An expert familiar with the condition’s symptoms and challenges will know which tests to do and how to interpret them.

To find an IgG4-RD expert, you can try these strategies:

  • Contact the National Organization for Rare Disorders (NORD) for a referral.
  • Reach out to the Genetic and Rare Diseases Information Center at the National Institutes of Health.
  • Use Google Scholar or PubMed to look for research papers on the disease and try contacting their authors.

The process of obtaining an IgG4-RD diagnosis may require a multidisciplinary approach, so several experts may need to be involved. Your care team may consist of:

  • a rheumatologist
  • a gastroenterologist
  • an ophthalmologist
  • a pathologist
  • a radiologist
  • an immunologist.

By collaborating and sharing their expertise, these IgG4-RD specialists can examine your symptoms and try to determine their cause. Remember that this may take some time as IgG4-RD can be difficult to recognize, even for experienced providers. But with the right specialists and a clear understanding of the condition, it’s possible to get an accurate diagnosis.


IgG4-RD News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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This site is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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