Allergy & Inflammation

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Home » Symptom Management » Allergy & Inflammation

Rashes, hives, stomach upset, body pain

The following is a collection of strategies used by the patient community.

As always, please consult your doctor before making any lifestyle changes. Not every solution will help for every person, the process can take a lot of trial and error.

Many with Long Covid experience symptoms
of Mast Cell Activation Syndrome (MCAS):

•    Heart related symptoms: rapid pulse (tachycardia), low blood pressure (hypotension) and passing out (syncope).

•    Skin related symptoms: itching (pruritus), hives (urticaria), swelling (angioedema) and skin turning red (flushing).

•    Lung related symptoms: wheezing, shortness of breath and harsh noise when breathing (stridor) that occurs with throat swelling.

•    Gastrointestinal tract symptoms: diarrhea, nausea with vomiting and crampy abdominal pain.

The Role of MCAS in Long Covid | With World Leading Specialist Dr Lawrence Afrin

The biological mechanisms of Long Covid are still somewhat of a mystery. But as we dig into the jigsaw looking for the pieces, one of the largest we’ve found is Mast Cell Activation Syndrome.

“There’s a large degree of overlap between the symptoms reported by long COVID patients and those seen in people with mast cell activation syndrome (MCAS), a disease where some of the mast cells become defective and spew too many chemical agents.”
– Dr. Afrin, Life Science, Antihistamines to treat long COVID: What you need to know

Symptom Management

Management techniques that are commonly used by the Long Covid community for MCAS symptoms include:


Mast cell stabilizer medications

Trigger avoidance, if possible

Low histamine diets have been successful for some, but not others

It is extremely important to speak to your doctor about symptoms of MCAS and any medications you have been using.

Our key observations are HRA (histamine receptor antagonist) reduces symptom burden in 72% of patients.

Glynne P, Tahmasebi N, Gant V, et al
Long COVID following mild SARS-CoV-2 infection: characteristic T cell alterations and response to antihistamines
Journal of Investigative Medicine 2022; 70:61-67.

Research on Allergy, Antihistimine, and MCAS in Long Covid

Long Covid Families continually adds to our collection of research and resources via AirTable

Published: February 2, 2022
Antihistamines for Postacute Sequelae of SARS-CoV-2 Infe

Published: November 1, 2021
Mast Cell Activation Symptoms are Prevalent in Long Covid

Published: March 22, 2021

Persistent Antiphospholipid Antibodies, Mast Cell Activation Syndrome, Postural Orthostatic Tachycardia Syndrome and Post-COVID Syndrome: 1 Year On

Published: January 2021
Risk factors for long covid in previously hospitalised children using the ISARIC Global follow-up protocol: A prospective cohort study

Published: September 10, 2020
Covid-19 hyperinflammation and post-Covid-19 illness may be rooted in mast cell activation syndrome

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