How to Prove a Long Term Disability Claim for MCAS

Understanding MCAS and Disability Claims

If you are dealing with mast cell activation syndrome (MCAS) and struggling to maintain consistent work due to unpredictable flares, fatigue, or cognitive symptoms, the issue is usually not just the diagnosis—it is whether your condition prevents you from working on a reliable, full-time basis.

MCAS claims are often difficult because symptoms can fluctuate, triggers are unpredictable, and many symptoms—such as brain fog, fatigue, or dizziness—are not easily measured through standard testing. Insurers often challenge these claims by labeling symptoms as “subjective” or inconsistent.

This page explains when MCAS can qualify for long term disability benefits, what evidence matters most, and why these claims are frequently denied.

Why MCAS Disability Claims Are Often Denied

MCAS claims are frequently denied not because the condition is not real, but because it is difficult to document in a way that aligns with how insurers evaluate disability.

Common denial arguments include:

• “Your symptoms are subjective”
• “There is no definitive diagnostic test”
• “Your condition is not consistently documented in your records”
• “You appear stable or improved at certain visits”
• “You can avoid triggers and continue working”

Can MCAS Qualify for Long Term Disability Benefits?

Yes, it is possible to receive long term disability benefits for Mast Cell Activation Syndrome (“MCAS”).  The physical symptoms (hives, low/high blood pressure, abdominal pain, fatigue, etc.) and cognitive symptoms (brain fog, anxiety, etc.) of MCAS can prevent some sufferers from working.  For some, MCAS symptoms can be minimized with treatment and limiting exposure to triggers.  However, if your MCAS flares are unpredictable and cannot be controlled, you may find yourself no longer able to continue working.

Approval depends on the severity and frequency of your symptoms and how they affect your ability to work on a consistent basis.

Disabling Symptoms of MCAS

MCAS symptoms often present as similar to allergic reactions.  One of the most serious symptoms of MCAS is anaphylaxis— a severe allergic reaction that, if left untreated, can close your airway and lead to shock and/or loss of consciousness.

These symptoms are important in a disability claim because they translate into functional limitations that can interfere with your ability to work. The symptoms for MCAS can affect several different body systems, including:

• • Respiratory (coughing; wheezing; chest tightness; anaphylaxis)
  • Dermatologic (skin itchiness; flushing; rashes; hives; swelling)
  • Cardiovascular (irregular blood pressure; lightheadedness; dizziness; rapid heart rate)
  • ENT (dry/itchy eyes; light sensitivity; nose and throat congestion)
  • Gastrointestinal (recurrent abdominal pain; irritable bowel; nausea; acid reflux; gastroparesis)
  • Nervous system (brain fog; poor short-term memory; anxiety; fatigue; headaches)
    
    

MCAS, EDS and POTS

MCAS commonly presents as a co-morbidity with Ehlers-Danlos Syndrome (“EDS”) and/or Postural orthostatic tachycardia syndrome (“POTS”).  If you are diagnosed with one of these syndromes, you may very well have one—or both—of the others.

Each of these syndromes is relatively new to the medical community, and there is no clear scientific explanation for why these diagnoses tend to overlap in patients.  Some researchers believe EDS can trigger MCAS due to the mast cells present in connective tissue.  Alternatively, some believe MCAS can cause EDS and POTS.

Regardless of the scientific reasoning behind the relationship between the three syndromes, many with MCAS share the same autonomic dysfunction symptoms caused by POTS and EDS.  If you have an MCAS diagnosis, it is worth discussing with your doctor whether you may have POTS and/or EDS as well.

When filing for long term disability, the more clarity you have of your own diagnoses, the better your chances are of filing a successful claim.

In disability claims, insurers often evaluate these conditions separately rather than considering their combined impact, which can lead to an incomplete assessment of your overall limitations. Having your doctor's explanation regarding totality of impact is often critical.

How MCAS Affects Your Ability to Work

In a disability claim, the key issue is not just which symptoms you experience, but how those symptoms affect your ability to function consistently in a work setting. Many people with MCAS can perform certain tasks at times, but struggle to maintain reliable performance over the course of a full workday or workweek. This issue of consistency, rather than isolated ability, is central to how disability insurers evaluate claims. 

Unpredictability of Symptoms

MCAS flares can occur without warning. A person may feel relatively stable one day and experience a severe flare the next. This unpredictability can make it difficult to maintain a consistent schedule, attend meetings, or meet deadlines. Employers generally expect reliability, and unpredictable symptom patterns can interfere with that expectation.

Cognitive Limitations

MCAS can cause cognitive symptoms such as brain fog, memory issues, and reduced concentration. These symptoms may interfere with your ability to focus, process information, and complete tasks efficiently. In roles that require sustained attention, problem-solving, or decision-making, even mild cognitive impairment can significantly impact performance.

Fatigue and Reduced Stamina

Chronic fatigue is common in individuals with MCAS. Even outside of acute flares, ongoing fatigue can limit your ability to sustain a full workday. You may find that your energy declines quickly, requiring frequent breaks or making it difficult to maintain pace and productivity throughout the day.

Environmental Triggers in the Workplace

Many workplaces expose individuals to common MCAS triggers, such as fragrances, temperature changes, cleaning products, or stress. These exposures can provoke symptoms even when you are otherwise stable. As a result, it may be difficult to control your environment well enough to prevent flares, particularly in office settings or public-facing roles.

How Do I Prove Long Term Disability For MCAS?

In order to get approved for disability benefits, your disability insurer will require explanation and proof of how your MCAS symptoms prevent you from working.

MCAS can be particularly challenging compared to other conditions.  MCAS flares can be erratic and unpredictable, and the severity of your symptoms may fluctuate day-to-day.  One day you feel relatively okay; the next, a flare leaves you fatigued, miserable, and dealing with severe discomfort.  Or, if a flare is bad enough, you may wind up in the hospital.

The challenge is explaining this pattern clearly to an insurer that is focused on measurable and consistent limitations.

Below are ways to gather strong evidence of your MCAS symptoms.

Getting A Diagnosis of MCAS

Having a definitive diagnosis of MCAS from a doctor well-versed in the condition will help bolster your disability claim.

There is not a singular test that can provide a definitive MCAS diagnosis.  Rather, your doctor will make a diagnosis by considering the following criteria:

• • You have symptoms commonly found in MCAS patients.  Your doctor will evaluate what symptoms you are experiencing, and whether they are associated with MCAS.  An in-person examination of your skin and a reading of your blood pressure, for example, will give your doctor an idea of whether you may have MCAS.
  • You respond to MCAS treatment.  MCAS is commonly treated with antihistamines, mast cell stabilizers, anti-leukotrienes, and other medications.  If your doctor prescribes one of these medications and it helps to curtail your symptoms, this substantiates an MCAS diagnosis.
  • Your test results indicate MCAS.  Blood and urine tests can show signs of MCAS. Testing can show mast cell “mediators” (chemicals released by mast cells) as higher than normal (especially if tested during a flare).  MCAS patients often have elevated levels of serum tryptase, which can be determined via blood test.  Urine tests can reveal abnormal histamine and prostaglandins levels, common in those with MCAS.
  • Other diagnoses are ruled out.  As mentioned earlier in this article, MCAS often overlaps with other diagnoses such as POTS and EDS.  Your doctor will consider whether another condition is responsible for your symptoms via examination or further testing.

If, once the diagnostic criteria is weighed, your symptoms and test results indicate MCAS, your doctor will give you an official MCAS diagnosis.  If testing is more ambiguous, your doctor may label your condition as “suspected MCAS.”

It’s important that your doctor is thorough with their evaluation of your MCAS.  The more evidence to support your MCAS diagnosis as legitimate, the better for your long term disability claim.

Documenting Your MCAS Symptoms

For those with MCAS, documenting symptoms can be especially challenging given that the syndrome is not well understood by the medical community.  Additionally, many of the symptoms can be “subjective” — meaning, they cannot be objectively measured in medical tests.

For example, your MCAS may cause episodes of brain fog and fatigue where you are unable to concentrate well enough to perform your work duties.  These symptoms are very real, but unfortunately difficult to prove to your long term disability insurer.  Long term disability insurers are typically skeptical of "subjective” or self-reported symptoms.

Strong MCAS claims combine medical documentation, consistent reporting, and evidence showing how symptoms affect your ability to function over time.

Here are a few ways to document your MCAS symptoms:

• • Start a paper trail with your doctor(s).  Objective medical evidence is always one of the strongest components of any long term disability claim.  Every time you treat with your doctor, they record a note on what transpired at that visit.  Make sure to explain all of your symptoms, both physical and cognitive, at each doctor visit.  If you have any visible signs of MCAS—say, a breakout of hives, intense face flushing, or a rash—your doctor will record this observation in their notes.  This will help substantiate your diagnosis and symptoms with your insurer.
  • Keep a symptom diary.  A “symptom diary” is just a written record of your MCAS symptoms day-to-day.  We often recommend our clients keep a symptom diary to explain how they felt, what their symptoms prevented them from doing, how much time they were able to spend sitting/standing/walking, and even include pictures of any visible symptoms (hives, face flushing, etc.).  This diary can be submitted to your disability insurer as evidence in support of your MCAS claim.
  • Undergo a Functional Capacity Evaluation (“FCE”).  A Functional Capacity Evaluation tests your physical function. This includes your ability to sit, stand, lift, carry, etc.  The results from this evaluation can demonstrate in objective measures how your MCAS symptoms impair your ability to work.  The FCE is conducted by a medical professional (such as an occupational therapist) and includes embedded “validity tests” that ensure the individual testing is putting forth their best faith effort.  Your disability insurer will consider this as supportive evidence of your MCAS. However, FCEs may not fully capture the unpredictable or episodic nature of MCAS symptoms. 

Stock video courtesy of Videezy and Pexels / Music courtesy of Bensound

Showing How Your MCAS Prevents You from Working in Your Occupation

Most long term disability insurance policies require you to initially prove you cannot work in your own occupation.  This means you likely only need to convince your disability insurer that you are disabled from your current job due to MCAS.  (If approved, you may need to show you cannot work in any reasonable occupation later down the line.)  Of course, you should always check your long term disability policy to see which definition of disability you must meet to receive benefits.

Beyond the medical evidence demonstrating your MCAS, any supportive testing results, and your own documentation (such as a symptom diary), you may consider vocational evidence.

Vocational evidence is evidence tying your MCAS symptoms to your specific occupation, and how those symptoms prevent you from performing your job duties. This is particularly important for individuals who can perform tasks intermittently but cannot do so reliably on a full-time basis. This evidence can include:

• • Your education history
  • Training qualifications / any accolades
  • Employment history
  • Job description

For example, your official job description may detail the physical requirements of your job—such as required travel for business meetings and conferences.  You can then argue that your MCAS symptoms limit you from physically performing that job requirement.

You may also consider a vocational assessment.  A vocational assessment is an evaluation of your occupational duties and how your MCAS affects your ability to perform them.  The assessment is performed by a professional with expert knowledge on the labor market and vocational rehabilitation.  The final assessment can serve as further evidence in support of your MCAS disability claim.

FAQs

Can I qualify for disability if my MCAS symptoms come and go?
Yes. The key issue is whether you can work consistently, not whether you have occasional good days.

Why does my insurer say my symptoms are subjective?
Many MCAS symptoms are not easily measured, which is why consistent documentation is important.

Can I still qualify if I avoid triggers?
Possibly. The question is whether you can realistically avoid triggers in a typical work environment.

How Can A Long Term Disability Attorney Help With An MCAS Disability Claim?

If you are filing a long term disability insurance claim for MCAS, or dealing with a claim denial/termination, an experienced ERISA disability attorney can help.

MCAS can be a challenging condition to substantiate in a disability claim.  A long term disability attorney can recommend additional testing, work with your doctor to obtain a letter of support, scour your medical records for any red flags, and help produce vocational evidence in support of your MCAS claim.

If you have MCAS and are considering filing for long term disability, talk to the New York disability lawyers at Riemer Hess.  We know what evidence LTD insurance companies find persuasive and are prepared to help you make the most convincing claim possible.  To arrange for a consultation with lawyers at Riemer Hess, call us at 212-297-0700 or click the button below to schedule a call.