COVID 19

Stanford doctor explains possible reason for hives after COVID recovery

ByLuz Pena KGO logo

Friday, July 22, 2022

Stanford doctor explains why people are getting hives post-COVIDStanford Infectious Diseases' Dr. Anne Liu explains why people are reporting getting hives after recovering from COVID-19.

PALO ALTO, Calif. -- Hives and rashes are some of the symptoms infectious diseases specialists are getting calls about after people test negative for COVID.

They may start on your knees or arms and move around your body.

"We get a lot of calls about hives -- specifically these welts that look like really big mosquito bites -- after people have had COVID or during an infection," Stanford's infectious diseases expert Dr. Anne Liu said.

Liu says these hives or rashes shouldn't be interpreted as allergies.

"The immune system getting stimulated by the virus," she said.

Dr. Robert Torrano with the Allergy & Asthma Associates of Northern California is noticing similar skin reactions during the recovery phase of infection. He says this happens with COVID, but also other viruses.

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"These are patients who note during the recovery phase, usually once the immune system has ramped up and is fighting the infection, that they start having outbreaks of hives," Torrano said. He then added, "They come and go. They'll pop up here. Then they'll pop up here."

Torrano recommends consulting with a medical professional but says in many cases these hives can go away with over-the-counter medication.

"If a patient takes a simple antihistamine like Benadryl or Claritin or Allegra or something like that over the counter, often the hives will respond and fade until the medication wears off," he said.

According to CDC data, "rashes" are part of the list of post-COVID infection symptoms.

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Luz Pena: "Why is it that after people test negative they start getting these rashes?"

Dr. Liu: "Sometimes it happens when people are still actively infected, but a lot of times it seems to be after the infection is clearing. That is partially probably because the immune system is still revved up, and the immune system is clearing the virus. And, as it's doing that, you can get misfiring within the immune system, resulting in rashes like this."

Torrano says that in many cases these rashes can go away after two hours, but in some cases may last several weeks.

"Usually they are going to go away in a few weeks. Up to six weeks is considered acute hives, or short-term hives. Over six weeks is considered long-term hives. I have seen very few chronic hive patients after COVID," he said.

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