Fever, headache, cough, runny nose — these are all symptoms we typically associate with influenza. However, sometimes, an unexpected and unusual symptom can pop up when infected with flu B: an itchy, red rash.
My 8-year-old son was recently diagnosed with flu B after he developed a fever and other typical flu symptoms. But he also had a bumpy rash all over his back and arms, which his doctor revealed is an uncommon side effect of the illness.
Studies have linked flu B with a rash, but as a mom, I had never heard of this symptom until my son’s appointment. This is likely due to the fact that a rash is generally associated with other conditions, so discovering a rash wouldn’t necessarily make you think you have contracted the flu.
HuffPost chatted with infectious disease experts to learn more about this surprising symptom and how it can be treated.
Why might a red rash be a side effect of Flu B and who experiences it the most?
“A rash is an uncommon finding associated with influenza; however, it can be seen in various viral respiratory illnesses and has been reported in cases of influenza B as well as influenza A H1N1,” Dr. Richelle Guerrero-Wooley, an infectious disease expert at Loma Linda University Health, told HuffPost.
“These rashes occur either due to the body’s inflammatory response to the virus, direct damage to the skin by the virus, or as a result of toxins emitted by the virus,” she explained.
Dr. Zachary Hoy, a board-certified pediatric infectious disease specialist at Pediatrix Medical Group, noted that a rash could be “due to the interaction of influenza virus with the body’s own antibodies (immune proteins) that can flare up during influenza infection.”
“Several studies found red (erythematous) rash with school children affected with influenza B during the 2013-2014 and during 2009 H1N1 pandemic,” he said.
Our experts said that children are more likely to experience a rash from influenza B (unfortunately for them), although, anyone could get it.
“While there is really no way to prevent who will develop a rash related to the flu or any other virus, it does occur primarily in children,” Guerrero-Wooley said.
And since a rash might be your only symptom of influenza B, it can be easily overlooked.
“Influenza B often has a milder presentation than influenza A, so people may not feel that sick,” Dr. Wesley Long, an associate professor of clinical pathology and genomic medicine at Houston Methodist Research Institute, told HuffPost. “Also, there are other viruses that cause rashes which are far more common than having a rash as a symptom of influenza B infection.”
These viruses include hand, foot and mouth disease, a common viral disease caused by coxsackie virus; soseola, a viral infection that mostly affects babies and children; Fifth’s disease, caused by Parvovirus b19; and others. He notes that rashes can also be caused by allergic reactions to medications or other irritants.
The best way to confirm what illness you or your child is experiencing is to get tested by a physician or take a home test.
How do you know if a rash is from the flu and not something else?
“Since there are many other more common causes of rashes like this, the presentation of other symptoms combined with specific viral testing is necessary to determine what is causing a rash during a febrile illness,” Long said.
Bottom line: You’ll have to get tested for the flu. “The main way to know if the rash is from the flu is if you test positive for the flu via nasal swab,” Guerrero-Wooley said.
If you are caring for someone with an influenza B rash, you can rest assured that the rash itself is not contagious.
“In the case of influenza B, the rash is not contagious,” Long said. “Influenza B is a respiratory illness, so transmission is usually through respiratory droplets, especially when an infected person talks, coughs or sneezes.”
Washing your hands is always a good idea after caring for someone with influenza B (and during flu season in general), but there isn’t necessarily a way to prevent an influenza B rash other than avoiding getting the illness at all.
“There doesn’t seem to be good prevention due to not understanding the mechanism of rash or exactly why it appears in certain patients,” Hoy said. “The best thing to do to prevent it is to prevent getting influenza.”
“Yearly flu vaccination, good hand hygiene and avoiding people that are sick are the best ways to prevent influenza,” he added.
How to treat a flu-related rash.
Like any rash, avoid scratching and use some anti-itch cream as necessary.
“Generally, there is no treatment to get rid of the rash,” according to Guerrero-Wooley, who added that rashes from the flu and other viruses are “typically self-limiting and will resolve on its own” or with the help of anti-itch topical lotions and ointments.
“However, if the rash is associated with any blistering, rapid spread, severe pain, or pus, then you should seek medical attention,” she noted.
There are a few things doctors can do if the rash is bothering you. “Many times, influenza treatment with antivirals such as oseltamivir seem to help with the rash,” Hoy said. “If it is itchy, some have recommended diphenhydramine.”
For my son, the rash went away on its own after a few days, along with his fever and other flu symptoms.
