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Rashes are a rare but documented side effect of COVID-19 vaccines. Bojan Story/Getty Images
  • New research finds that some people develop a red, itchy, swollen, or even painful rash where they received their COVID-19 vaccine shot.
  • However, this reaction is rare and occurs only in a small percentage of people.
  • Experts say these reactions are relatively minor and are not a reason to avoid the COVID-19 vaccine.

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According to the Centers for Disease Control and Prevention (CDC), some people have reported a red, itchy, swollen, or even painful rash where they received their COVID-19 vaccine shot.

This reaction can begin from a few days to over a week after the first dose, and sometimes rashes are quite large. These rashes, sometimes called “COVID arm,” can also occur on other parts of the body.

New research recently published in JAMA Dermatology looks into how common these reactions are and how frequently they recur after getting your second dose.

For the study, a team of allergists at Massachusetts General Hospital (MGH) studied 49,197 Mass General Brigham employees vaccinated with an mRNA COVID-19 vaccine.

Over 40,000 of them completed at least one symptom survey after the first dose of vaccine.

Researchers found skin reactions were reported by only 776 of survey respondents after the first dose.

The most common skin reactions were rash and itching other than at the injection site, and the average age of those reporting a reaction was 41.

Skin reactions were much more common in females (85 percent) than males (15 percent) and differed by race, with whites most affected, followed by Asians, and African Americans affected the least.

Among the 609 individuals who reported skin reactions to the first dose and then received a second dose, 508, or 83 percent, reported no recurrent skin reactions.

For those with no skin reaction to the first dose, a little over 2 percent reported skin reactions after the second dose, with rash and itching being the most common.

“This is the first information we have on risk of recurrence of skin reactions after dose 2 when there is a dose 1 reaction,” lead researcher Dr. Kimberly G. Blumenthal, co-director of the Clinical Epidemiology Program within MGH’s Division of Rheumatology, said in a statement. “Our findings could provide critical reassurance to people with rashes, hives, and swelling after dose 1 of their mRNA vaccines.”

According to Dr. Michele S. Green, a dermatologist at Lenox Hill Hospital in New York, localized reactions to the vaccine are fairly common and not a cause for concern — and definitely not a reason to postpone your second dose.

She noted that some patients have also experienced swelling at the site of facial cosmetic dermal fillers after having the COVID vaccine, and these reactions are different than a rare form of allergic reaction to the vaccine — anaphylactic shock.

“Cutaneous reactions are not a contraindication to the vaccine or re-vaccination and are not cause for alarm,” emphasized Green. “These cutaneous rashes are distinct from immediate anaphylactic reactions, which needs prompt medical attention.”

Green explained that it’s believed that irritation or swelling at the injection site is a type of dermal hypersensitivity reaction related to our immune system. She believes it may be associated with immune cell response to a component of the vaccine.

“It is still not clear why some patients develop this reaction,” she said, adding that some people could experience reactions on other parts of the body that include:

To relieve the discomfort of these reactions, Green recommends the use of topical steroids, applying warm compresses, or taking an over-the-counter pain reliever.

According to the CDC, anaphylactic shock has been detected in only 21 out of 1,893,360 first doses of the Pfizer COVID-19 vaccine – a rate of 11.1 cases per million doses.

Locations distributing COVID-19 vaccines are required to observe a waiting period for anyone who was immunized and have epinephrine shots available to treat those few people affected.

“Yes, some patients may develop a more severe reaction to the mRNA COVID vaccine,” said Green. Anaphylactic reactions “in less than 4 hours can be a cause for concern, and [indicate you] should seek medical care.”

Some people develop a red, itchy, swollen, or even painful rash where they received their COVID-19 vaccine shot. New research finds this reaction occurs rarely and occurs only in a small percentage of people.

The study also found that women are most affected and African Americans are the least.

Experts say this reaction is no cause for concern and not a reason to postpone your second vaccine dose.

They also say that some people experience a more severe reaction in very rare instances, but vaccine distribution sites are ready to treat the affected people.