Table of Contents
- Key Points
- Background: When Covid Looks Like an Allergic Reaction
- Patient Story: Morgan McElroy's Experience
- What Allergy Experts Say
- How the Immune System Causes Hives and Swelling
- A Different Kind of Covid Rash
- Key Findings at a Glance
- Clinical Implications for Patients
- Limitations and What's Still Unknown
- Recommendations for Patients
- Frequently Asked Questions
- Source Information
Key Points
- Covid-related rashes and swelling are not allergic reactions to the virus, experts say.
- An overactive immune system releases histamine during infection, mimicking allergy symptoms.
- These reactions are usually benign and resolve with antihistamines or steroids, such as prednisone.
- This hives-and-swelling response is different from frostbite-like covid toes.
- Seek emergency care for throat swelling, difficulty breathing, or rapid severe swelling.
Background: When Covid Looks Like an Allergic Reaction
As the coronavirus pandemic continues, doctors are seeing a wide range of symptoms beyond the classic fever, cough, and shortness of breath. Some patients report skin rashes and swelling that look frighteningly like an allergic reaction. These symptoms have prompted many to wonder: Can a person actually become allergic to covid-19? Experts say the answer is “highly unlikely.”
The confusion is understandable. The symptoms — sudden hives, itchy red splotches, and swelling of the face, lips, or even throat — are exactly what many people expect from an allergy to food, medication, or other triggers. But when these symptoms appear during a viral infection, they usually mean something different is going on inside the body.
The topic has captured widespread attention, largely due to a viral TikTok video by Morgan McElroy that has been viewed more than 4.6 million times. In the video, McElroy documented her swollen face and body rash, saying, “I’m allergic to covid.” That statement, while attention-grabbing, is misleading according to allergy specialists.
Patient Story: Morgan McElroy's Experience
McElroy, 20, lives with her mother in Dayton, Ohio. Earlier this month, she suddenly lost her sense of smell and taste. Since her mother had recently started showing symptoms of covid-19, McElroy correctly guessed that she too had been infected.
What she didn’t expect was to end up in the emergency room a day later. She woke up on Dec. 3 with an unusual itching sensation inside her mouth. She took Benadryl (an over-the-counter antihistamine) and lay down for a nap. When she woke up a couple of hours later, the sight in her bathroom mirror sent her running for her mother.
“My face was absolutely swollen to the max,” McElroy said. “I immediately went in panic mode.” She noted that it also felt like her throat was swelling, which prompted her mother to call 911. By the time the ambulance arrived, her symptoms had worsened. “It was getting pretty gross, and my lips were just absolutely humongous. Everything was just massive,” she recalled.
At the hospital, McElroy was given two steroids through an IV and liquid Benadryl. In addition to the swelling, much of her body was covered in itchy red splotches. Doctors asked the standard allergy questions: “Are you using new laundry detergent? Did you eat anything new?” McElroy explained that she had been quarantining for over a week and hadn’t done anything new. “I promise you, it’s nothing that I did. It just popped up out of nowhere,” she said.
After about two hours at the hospital, she was sent home with a prescription for Prednisone, an anti-inflammatory medication, and an explanation that left her with more questions than answers. “What my doctor said in there was, ‘I think it’s covid-related,’ ” she said. “But that’s all the explanation that they had.”
What Allergy Experts Say
Experts who reviewed McElroy’s case say her symptoms are not a sign of an actual allergy to the novel coronavirus. “She’s not allergic to covid,” said Purvi Parikh, an allergist and immunologist with the Allergy and Asthma Network who has seen several covid patients reporting similar reactions. Parikh explained that rashes are “frequently known consequences of viruses and usually benign.” She added, “Actual allergies can be life threatening. . . . It would be misleading to suggest you could be allergic to a virus.”
David Stukus, a member of the covid-19 response task force for the American Academy of Allergy, Asthma and Immunology, agreed. He noted that covid can be a systemic disease, affecting many parts of the body. “When it comes to covid-19, anything and everything is in play,” he said.
Stukus explained that viruses and other infections are common triggers for seemingly random episodes of hives and swelling. “It can be very dramatic, especially when somebody’s face swells; nobody wants to see that,” he said. “It can be very debilitating because it can be severely itchy, but it’s very different than an allergic reaction and anaphylaxis (a severe, potentially life-threatening allergic reaction).”
Panagis Galiatsatos, an assistant professor of medicine at Johns Hopkins and a pulmonary and critical care doctor who works with covid patients, offered a plain-spoken summary: “It just means her immune system doesn’t like covid, no different than every other human being’s immune system.”
How the Immune System Causes Hives and Swelling
To understand why a virus can cause allergy-like symptoms, it helps to know a bit about the immune system. When the body detects an infection, the immune system mounts a defense. Sometimes, that defense becomes “a little too overactive in its task to clear the infection,” Parikh said. This overactivity can trigger the release of histamine — the same chemical that causes symptoms in a classic allergy.
“The virus kind of mimicked an allergy,” Parikh said. This explains why antihistamines like Benadryl provide relief, even though the root cause is not an actual allergen.
Stukus added that covid may “unmask” people who are already predisposed to hives and swelling. People with environmental allergies, food allergies, or other allergic conditions have “allergy cells that are really good at releasing this histamine chemical,” he said. When they get sick with an infection, their immune system goes into overdrive, and those cells can be activated as a byproduct.
Aside from the virus itself, other factors could contribute to rashes and swelling during an infection. These include drinking alcohol, vigorous exercise, and taking common pain relievers such as Advil or Motrin (ibuprofen), which can increase blood flow and temporary inflammation in the body.
A Different Kind of Covid Rash
The allergy-like reaction McElroy described is not the only skin symptom tied to covid-19. Doctors have also observed unusual frostbite-like patches on people’s toes and sometimes fingers — a condition that became popularly known as “covid toes.” Parikh noted that these types of rashes are believed to be distinct from the hives-and-swelling reaction. “What McElroy described on TikTok is more similar to what we see with viruses in general,” she said.
Both types of rashes are important clues for doctors, but they represent different immune responses. The frostbite-like patches may indicate a hidden coronavirus infection, especially in younger patients, while the hives-and-swelling response is a more generic virus-triggered reaction.
Key Findings at a Glance
- Not a true allergy: Rashes and swelling caused by covid-19 are not allergic reactions to the virus itself.
- Common in viral infections: Viruses are frequent triggers for hives and angioedema (swelling beneath the skin).
- More common in children: These reactions are most often seen in young children, which may be why adults feel more frightened when they happen to them.
- Usually benign: In most cases, the symptoms are not dangerous and resolve on their own or with anti-inflammatory medications.
- Different from other covid rashes: This reaction is separate from frostbite-like toe and finger patches.
- Mechanism: An overactive immune system releases histamine, mimicking an allergy.
- Possible contributing factors: Alcohol, vigorous exercise, and certain medications (e.g., ibuprofen) may amplify symptoms.
Clinical Implications for Patients
If you developed hives or swelling during a covid-19 infection, it’s natural to worry. But experts stress there is usually no need to panic. The symptoms are more than likely a sign that your immune system is working hard to fight the virus, not that you’re in immediate danger.
However, the distinction between an allergic reaction and infection-triggered hives matters for treatment. In a true allergy, the trigger must be avoided, and emergency treatment may be required. In virus-triggered hives, the focus is on symptom relief — through antihistamines like Benadryl, anti-inflammatory steroids, or other supportive care.
Patients should still take any swelling seriously, especially if it involves the throat or feels like it’s affecting breathing. In McElroy’s case, her throat-swell sensation prompted a 911 call. Emergency care is always appropriate if you’re having trouble breathing, or if swelling is severe and rapid.
Limitations and What's Still Unknown
This understanding of covid-related rashes and swelling comes from expert clinical experience, not from a controlled scientific study. The pandemic is new, and knowledge is still evolving. As Stukus said, “We have a lot to learn in regards to all the nuances involved with this infection.”
It is also unclear why some patients develop these dramatic symptoms while others do not. The possible link to pre-existing allergies is a theory, not a proven rule. Doctors continue to collect data on the many skin, neurological, and immune-related effects of covid-19.
Recommendations for Patients
Experts offer the following advice for anyone worried about covid-related rash or swelling:
- Stay calm. Remember that these symptoms are typically not a sign of a dangerous allergy to covid-19.
- Call your doctor first. As Stukus advised, “If you have any concerns about your personal health, always call your doctor first.” They can recommend appropriate treatment and help you decide if you need in-person care.
- Use trusted resources. Look to organizations like the American Academy of Allergy, Asthma and Immunology or the CDC for up-to-date information instead of social media alone.
- Take medications as directed. Over-the-counter antihistamines (like Benadryl) or prescription anti-inflammatories (like Prednisone) can relieve symptoms when used under medical supervision.
- Seek emergency care for serious symptoms. Go to the ER if you experience throat swelling, difficulty breathing, or any sign of anaphylaxis.
Frequently Asked Questions
Can you develop a true allergy to the covid-19 virus?
No. Allergy experts say being truly allergic to the coronavirus is highly unlikely. Hives, itching, and facial swelling during covid are caused by the immune system overreacting to the infection and releasing histamine. This mimics an allergy but is not one, and it typically resolves with anti-inflammatory treatment.
Why did I get hives and facial swelling while sick with covid-19?
When your body fights a viral infection, the immune system can become overactive and release histamine, the same chemical that causes allergy symptoms. This results in hives and swelling. The virus essentially mimics an allergic reaction, even though no true allergen is involved. Other factors like alcohol, exercise, or ibuprofen may also contribute.
Is this covid-related rash and swelling dangerous?
Experts say these reactions are usually benign and not life-threatening. They can be dramatic and severely itchy, but they are very different from a true allergic reaction or anaphylaxis. However, if you experience throat swelling, difficulty breathing, or rapidly severe swelling, seek emergency care immediately.
What should I do if I develop a rash or swelling during covid-19?
Stay calm and call your doctor first. They can recommend appropriate treatment, such as antihistamines like Benadryl or prescription anti-inflammatories like prednisone. Use trusted resources for information. If you have throat swelling, trouble breathing, or signs of anaphylaxis, go to the emergency room.
Is this reaction the same as 'covid toes'?
No, they are different. The hives-and-swelling reaction described with covid is similar to what is seen with many viral infections. Covid toes are frostbite-like patches on toes or fingers and are believed to represent a distinct immune response. Both can be signs of covid, but they are separate conditions.
Are children more likely to get this type of covid rash?
Experts note that virus-triggered hives and swelling are most often seen in young children. That may be why adults, who rarely experience this, feel more frightened when it happens to them. However, it can occur in anyone, and the reaction is typically benign and treatable.
Will taking Benadryl help this covid-related rash?
Yes, antihistamines like Benadryl can provide relief because the symptoms are caused by histamine release. The root cause is not a true allergen, but these medications help reduce itching and swelling. Always use medications as directed and under medical supervision, especially if you have other health conditions.
Should I get a second opinion for covid-related hives and facial swelling?
If you develop hives or facial swelling during a covid-19 infection, a second opinion can help confirm that your symptoms are not a true allergy to the virus. Experts say these reactions are usually benign and caused by an overactive immune system releasing histamine, not an allergic response. A second opinion can reassure you that antihistamines or anti-inflammatory steroids like prednisone are appropriate, and help you decide if emergency care is needed for throat swelling or breathing difficulty. Diagnostic Detectives Network provides independent expert second opinions.
Source Information
Original article title: Covid-related rashes and swelling not likely signs of allergy - The Washington Post
Author: Allyson Chiu
Publication: The Washington Post, December 10, 2020
This patient-friendly article is based on peer-reviewed research.
