Before COVID, you could eat anything, wear any perfume, and walk down the detergent aisle without a second thought. Now you get hives out of nowhere. Foods you’ve eaten your whole life make you flush or cramp. Strong smells tighten your throat.
A growing number of people describe exactly this, and researchers have started paying attention.
What the research shows
A 2021 study in the International Journal of Infectious Diseases (Weinstock et al.) compared people with long COVID with people who had not had long COVID. Symptoms consistent with mast cell activation were significantly more common in the long COVID group. The pattern of symptoms was similar to that seen in people already diagnosed with MCAS.
That’s an important observation. It is also an early one.
What we don’t know yet
We want to be clear about the limits of current research:
- It isn’t established that COVID causes MCAS. Studies showing more mast cell symptoms after COVID don’t prove cause and effect.
- The mechanism is unconfirmed. Proposed explanations include persistent immune activation after infection, viral components interacting with mast cells, and unmasking of a pre-existing tendency toward mast cell reactivity. None of these has been proven.
- Symptom questionnaires aren’t a diagnosis. Many long COVID studies used symptom surveys rather than mediator testing.
What this means in practice: new mast cell–type symptoms after COVID are worth taking seriously and evaluating properly. But the label shouldn’t be assumed without looking at the evidence in your own case.
Symptoms people report after COVID
- New hives, itching, or flushing
- Reactions to foods, alcohol, or medications that were previously fine
- Sensitivity to fragrances, smoke, or chemicals
- Abdominal cramping, diarrhea, or bloating after meals
- Throat tightness or nasal congestion without infection
- Racing heart or lightheadedness during flares
Overlap with long COVID
Mast cell symptoms after COVID rarely appear alone. They often come with fatigue, brain fog, and a racing heart on standing. Sorting out which symptoms belong to which process helps focus the evaluation.
How it is evaluated
- A clear timeline: which symptoms are new since COVID and which existed before.
- The body-system pattern and triggers: food, heat, smells, stress, exertion.
- Timed mediator testing during flares where appropriate, compared with your own baseline.
- Ruling out other causes: new IgE allergy, alpha-gal syndrome (Lone Star tick bites are common in Oklahoma), celiac disease, medication reactions, and thyroid problems.
When to get emergency care
Call 911 for:
- throat or tongue swelling,
- trouble breathing,
- widespread hives with dizziness, or
- fainting.
Use a prescribed epinephrine auto-injector as directed.
Serving Oklahoma City, Tulsa, and all of Oklahoma
Venturis Clinic sees patients from Oklahoma City and surrounding areas, including Tulsa, and from across Oklahoma. Learn more on our MCAS in Oklahoma City page.
Frequently asked questions
Can COVID cause MCAS? Research shows mast cell–type symptoms are more common in long COVID, but a direct causal link hasn’t been established.
Why am I suddenly reacting to foods after COVID? Possible reasons include mast cell activation, new allergies, alpha-gal syndrome, or changes in gut function. Each is evaluated differently.
Will these reactions go away? Some people improve over time. Identifying triggers and the underlying pattern is a useful first step.
Should I get tested for MCAS if I have long COVID? If you have recurrent symptoms across multiple body systems with clear triggers, it’s reasonable to evaluate for it.
New reactions since COVID? Book a free 15-minute discovery call, or learn more about MCAS care in Oklahoma City.
This page is for educational purposes and is not a substitute for individual evaluation.
By Alvin Philipose, DC, ICCP
Sources
- Weinstock LB, et al. Mast cell activation symptoms are prevalent in Long-COVID. International Journal of Infectious Diseases. 2021;112:217–226.
- Valent P, et al. International Archives of Allergy and Immunology. 2012;157(3):215–225.