Doctors dispute claim that COVID-19 pneumonia is actually an allergic reaction

It's well known that a severe case of COVID-19 can cause a series of complications, including pneumonia, an infection that causes inflammation of the air sacs in the lung.

But according to a claim spreading on social media, pneumonia triggered by COVID-19 isn't pneumonia at all, but rather a type of fast-occurring allergic reaction to the virus.

Multiple Facebook users reposted a message claiming that the condition occurring in COVID-19 patients is really "mast cell degranulation" of the lungs. 

"Put simply, it's an allergic reaction occurring after the viral phase ends, most likely to something in the viral particles left over after the body deals with the virus," the post says. "The reason you can't tell it's an allergic reaction is because it's happening in the lungs, so you experience only symptoms of chest tightness and fatigue!"

The posts were flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.) 

The Facebook posts cite a doctor's findings as evidence. However, doctors we spoke to disputed the theory, and reiterated that COVID-19 pneumonia is just that — pneumonia. 

For clarification on the term "mast cell degranulation," we turned to the American Academy of Allergy, Asthma and Immunology. It describes mast cells as allergy cells responsible for immediate allergic reactions. During an allergic reaction, these cells are triggered to release "mediators," which can bring on symptoms of an allergy, such as swelling or shortness of breath. The release of these mediators is called degranulation.

The Facebook post cites the findings of Dr. Shankara Chetty, who is described as a natural science biologist and general family practitioner in South Africa. 

Chetty has become known for his belief that COVID-19 is "allergic in nature." He has promoted alternative treatments on platforms like YouTube. Other interviews with Chetty have also been published to social media platforms such as Twitter.

The posts claim that Chetty had treated thousands of patients and monitored differences in the progression of symptoms between people with regular pneumonia and those with COVID-19 pneumonia. Chetty noticed that patients with COVID-19 pneumonia symptoms suddenly got worse after several days, "unlike" regular pneumonia, the posts say. And he observed that the patients’ flow of oxygen wasn’t restricted, but that they faced a rapid restriction in lung expansion, "unlike pneumonia."

"It was then that he recognized the similarity this condition had with an allergic reaction," the posts read. "The second an allergic reaction happens, inflammation creates instant symptoms."

The claim is "unintelligible nonsense," said Dr. Mark Schleiss, a pediatrics professor and faculty member in the Division of Pediatric Infectious Diseases at the University of Minnesota.

COVID-19 pneumonia is not an allergic reaction, Schleiss said, but mast cell activation — the triggering of the release of mediators — is one of the body’s reactions to COVID-19 pneumonia.

"Mast cell activation is just a part of the myriad of downstream phenomena that occur with viral pneumonia," Schleiss said. 

Many things other than allergies can trigger mast cell activation, said Schleiss, including eczema, swelling from an injury, or an infection like pneumonia. It’s a part of the reaction to something — not the cause.

He likened the Facebook claim to a person suffering a broken nose from a fistfight, and blaming the redness and swelling on mast cell activation, rather than the punch or the fracture.

Dr. Pranatharthi Chandrasekar, division chief of infectious diseases at Wayne State University in Detroit, said people shouldn’t even use the word "allergy" in describing COVID-19 pneumonia. That’s not how the illness works. 

"It’s wrong to say. It gives the wrong representation that … the person may be allergic to the virus," Chandrasekar said. "This is (a) virus attacking the body, and in return, the immune system is reacting."

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Chandrasekar explained how COVID-19 can turn into pneumonia: Within seven to 10 days, the virus first attacks the throat, and then begins descending into the lungs. It attacks the lungs, which causes viral pneumonia. 

"The immune system is triggered because of the viral illness, so the immune system (goes) astray," he said. 

Dr. Meilan King Han, professor of medicine in the division of pulmonary and critical care at the University of Michigan, pointed to a published study in the open-access journal Nature. It showed that  COVID-19 has triggered mast cell degranulation, which resulted in hyper-inflammation and injury to the lung. But, Han said, this certainly isn’t the only thing that the virus does to our lungs.

Symptoms of COVID-19 induced pneumonia include shortness of breath, increased heart rate and low blood pressure. Houston Methodist, the big hospital and health system, says that COVID-19 pneumonia can occur in both lungs, and recovery can take from several weeks up to many months. Healthline reports that treatment for COVID-19 pneumonia often requires oxygen therapy, and antibiotics if the viral pneumonia causes a bacterial infection. 

"After severe pneumonia, lung capacity is reduced, and muscles may be weak from being so ill," Houston Methodist says on its website.

Both Chandrasekar and Schleiss agree that COVID-19 induced pneumonia is unlike other forms of pneumonia. But just because it can strike quickly, that doesn’t mean it’s similar to allergies. 

"I have been at the bedside of children who died of COVID pneumonia, I’m sad to say," said Schleiss. "It comes on pretty fast." 

A widespread Facebook claim states that COVID-19 pneumonia is "actually mast cell degranulation of the lungs," which is an allergic reaction. 

Doctors we spoke to said there is no basis for the claim. 

They said mast cell activation is a part of the body’s reaction to COVID-19 pneumonia. It’s an immune response that can be caused by pneumonia or other triggers, such as an injury or skin condition.

We rate the claim False.