Getting Disability Benefits for Undifferentiated or Mixed Connective Tissue Disease

Learn how you can qualify for disability benefits with mixed connective tissue disorder or undifferentiated connective tissue disorder.

By , Attorney · Mitchell Hamline School of Law

Connective tissues, made up of collagen and elastin, hold other tissues and organs in the body together. Connective tissue diseases are various medical conditions that affect these tissues. When a person has a connective tissue disease (CTD), the connective tissues become inflamed, which can harm the parts of the body the tissues connect. There are many different types of CTDs, including:

This article is about the last two types of connective tissue disease: mixed connective tissue disease and undifferentiated connective tissue disease. (Visit the above links for articles about the other types of CTDs.)

What Is Mixed Connective Tissue Disease?

Mixed connective tissue disease (MCTD) is a rare autoimmune disorder that's often called an "overlap disease," because it's a medical condition that has obvious symptoms of two or more connective tissue diseases. For example, a patient might have symptoms of systemic lupus and systemic vasculitis but blood tests that confirm rheumatoid arthritis.

Generally, overlap syndromes aren't as common as single connective tissue diseases; for example, mixed connective tissue disease occurs at 1/20th the rate of lupus. Mixed connective tissue disease can occur in people at any age, but it's more common in women under 50.

Symptoms of MCTD

People with mixed connective tissue disease have symptoms in common with those who have other connective tissue diseases, including lupus, scleroderma, and rheumatoid arthritis. The most common symptoms include:

  • fatigue
  • swollen fingers or stiff fingers with limited movement
  • muscle and joint pain
  • trouble with the esophagus, such as heartburn or difficulty swallowing
  • pulmonary hypertension (high blood pressure in the blood vessels of the lungs), and
  • Raynaud's phenomenon (reduced blood flow to the fingers and toes that causes sensitivity, numbness, and loss of color in the affected areas).

Diagnosing MCTD

A few indicators can point to mixed connective tissue disorder rather than a single connective tissue disorder like lupus or rheumatoid arthritis, such as:

  • a high amount of a particular antibody in the blood, called "ribonucleoprotein"
  • an absence of severe kidney problems (which are usually seen in people with lupus)
  • severe arthritis and pulmonary hypertension (which aren't typically seen in people with lupus or scleroderma), or
  • Raynaud's disease (this occurs in only 25% of people with lupus).

Patients with MCTD may meet the diagnoses for several connective diseases at the same time.

What Is Undifferentiated Connective Tissue Disease?

Undifferentiated connective tissue disease (UCTD) can have similar symptoms to MCTD, but it's not an overlap syndrome. UCTD has vague characteristics of one or more connective tissue diseases but doesn't actually meet enough of the criteria to be diagnosed as one of the other types of connective tissue diseases.

Symptoms of UCTD

The most common symptoms that people with undifferentiated connective tissue disease experience include:

  • rashes that get worse with sun exposure
  • low-grade fever (usually under 100°F)
  • joint pain and swelling
  • dryness of the eyes and mouth, and
  • Raynaud's phenomenon (reduced blood flow to the fingers and toes that causes sensitivity, numbness, and loss of color in the affected areas).

Prognosis for UCTD

For approximately 20% to 40% of people with undifferentiated connective tissue disease, the symptoms progress to a more defined connective tissue disease, usually within three years. Another 10% to 30% of people with UCTD will experience remission of their symptoms, and the remainder will continue to experience the mostly mild symptoms of the disease.

What Causes Undifferentiated or Mixed Connective Tissue Disease?

Undifferentiated and mixed connective tissue diseases are both autoimmune disorders, where the immune system mistakenly attacks the body's own healthy tissues. The cause of undifferentiated or mixed connective tissue disease isn't usually known, but some connective tissue disease may be caused by:

  • a family history of connective tissue or other autoimmune diseases
  • exposure to toxic chemicals (like polyvinyl chloride or silica)
  • exposure to ultraviolet light
  • lack of nutrition, such as vitamins C and D, and
  • infections.

Can You Get Disability Benefits for MCTD or UCTD?

A diagnosis of mixed connective tissue disorder or undifferentiated connective tissue disorder is not enough to get disability benefits. But if you're experiencing moderate to severe limitations that prevent you from working for 12 months or more, and you have good medical records, the Social Security Administration ("Social Security") may approve you for benefits.

Social Security has two ways you can qualify for disability benefits:

  • Meeting a "listing." Social Security has a disability evaluation handbook that outlines the criteria for disability for various medical conditions. Social Security calls these rules "listings."
  • Being unable to work due to your limitations. Even if you don't meet a listing, you may still be eligible for disability benefits if you can prove that you have a severe medical impairment that makes you unable to do work activities.

Meeting a Listing

Social Security may evaluate your condition under listing 14.06, for "undifferentiated and mixed connective tissue disease." The listing states that you must have:

  • two organs or body systems affected, with one affected to at least a "moderate" level of severity, and
  • at least two signs or symptoms of the disease, including severe fatigue, fever, malaise (feeling unwell), or involuntary weight loss.


  • repeated manifestations of UCTD or MCTD, with at least two of the signs or symptoms (severe fatigue, fever, malaise, or involuntary weight loss), and
  • at least one of the following at a "marked" (severe) level of severity:
    • limitations of activities of daily living, such as walking, dressing, or bathing
    • limitations in being able to function socially, or
    • limitations in completing tasks in a timely manner due to being unable to concentrate, keep pace, or work for an extended period of time.

Meeting the criteria explained in this listing requires good medical evidence from your doctors.

Medical Evidence That Social Security Needs to Decide Your Claim

You must have a medical diagnosis of a severe condition that's backed up by medical findings like lab tests, not just your reports about fatigue or feeling unwell. Social Security will evaluate your claim based on medical evidence like lab tests, CT scan results, and your doctors' treatment notes. Social Security might also send you for an independent exam by one of their doctors or might ask your doctor to complete a questionnaire about your limitations.

To get approved for disability for mixed or undifferentiated connective tissue disease, your records must include the following:

  • a diagnosis of undifferentiated or mixed connective tissue disease (preferably by a rheumatologist, a doctor that specializes in autoimmune and inflammatory diseases)
  • lab results, such as blood work, confirming the presence of antibodies
  • CT scan, x-ray imaging, or ultrasound to show lung, joint, or abdominal damage
  • doctor's notes reflecting the frequency and severity of your symptoms, and
  • a history of any treatments you tried and whether they helped or caused side effects.

Being Unable to Work Due to MCTD or UCTD

Most disability claims that are approved for benefits don't actually meet the criteria of one of the listings contained in Social Security's blue book. Instead, Social Security approves them because the applicants' limitations make them unable to perform their previous jobs and they're unable to transition into another type of work.

To decide whether you're unable to work, Social Security will look at your medical records to see if there's enough evidence you have a serious medical condition that limits your ability to do many work-related activities. A claims examiner will first determine your residual functional capacity (RFC), which is the most intensive work you can still do (medium, light, or sedentary), despite the limitations caused by your medical condition. For example, if you have severe undifferentiated or mixed connective tissue disease, your doctor might limit you to standing or walking a certain number of hours per day. You might also experience an aching pain and swelling in your joints, as well as numbness in your hands or toes, that could prevent you from doing finger work or lifting heavy items.

An RFC for someone suffering from severe MCTD or UCTD might include the following limitations:

  • walk and stand for four hours of an eight-hour workday
  • sit for four hours of an eight-hour workday
  • lift and carry no more than twenty pounds occasionally and ten pounds frequently
  • stoop, crouch, crawl, kneel, or bend only occasionally
  • reach, handle, or finger with the bilateral upper extremities only occasionally
  • never climb ladders, ropes, or scaffolds
  • avoid concentrated exposure to extreme cold, wet, or humidity, and
  • no exposure to vibrations such as vibratory tools or machinery.

Someone with these limitations would likely be unable to perform most jobs, because they would be unable to perform most of the physical requirements of even sit-down work. For more information on how the SSA decides whether your RFC prevents you from doing any jobs, see our section on disability determinations based on RFCs.

How Do I Apply for Social Security Disability Benefits?

An easy way to apply for Social Security disability benefits is to file your claim online at You may also file a claim over the phone by contacting Social Security at 800-772-1213, but be prepared for long wait times. For more information, please see our article about applying for Social Security disability benefits

Published November 30, 2021

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