A nurse from Blair, Nebraska, has shared an image of her son's infected skin over social media to warn other unknowing parents about a new flu symptom.

Brodi Willard narrated on Facebook that she first discovered the hives when her son Seb came home from school last Friday. He was scratching relentlessly, and each time he did, it seemed as though the condition only became worse.

As the remedy, Willard and her husband tried giving Seb a bath and letting him wear a fresh set of clothes. However, such remedy did not help even just a little. This is when the frustrated mother decided to call the pediatrician.

Flu Season 2018: 'Never Heard' Symptom

Willard learned from the doctor that two other kids came to the clinic earlier in the day, manifesting exactly the same symptoms as her son, and both tested positive for influenza. Such prompted her to take him in for testing, which later revealed that he had actually contracted the influenza B virus.

"He has had no symptoms. No fever, no cough, and no runny nose. He only has hives. Please keep watch on your children so if they develop hives, please call your pediatrician," she writes in a Facebook post.

Her post has elicited an overwhelming amount of response from other social media users, with some of them claiming that their children are also suffering from the same case.

Another mother from Texas, Shannon Silvernail, extended her gratitude to Willard as the post alerted her to get her son tested as well. Similarly, he woke up with the hives on Monday without exhibiting any common symptom of the flu.

Silvernail shared that after testing, he was found positive for the influenza A virus and was then prescribed Tamiflu. This particular case is a result of an "antigenic shift", says the CDC. This type of mutation creates a new influenza A subtype that most people are not immunized against.

Such change happened during spring of 2009 when an H1N1 virus underwent natural mutation. With a new genetic combination, it infected thousands of people, causing a deadly epidemic.

As of Feb. 1, Willard's post has been shared more than 235,000 times on Facebook and has received more than 14,000 comments and 30,000 reactions.

Flu Virus Mutate All The Time, Experts Say

The development of a completely new symptom is not an impossibility, as health experts explained that influenza viruses are always mutating. Currently, there are several strains of the influenza virus being passed around resulting in an extended flu season which is projected to continue into March.

Dr. Julie Linderman, of Inwood Village Pediatrics in Texas, cautions parents that if their child's flu does not see any progress within day 3 or 4 and is accompanied by rising temperatures and more coughing, they should immediately seek medical attention.

Seb was also given Tamiflu and is now more active than the previous days, according to Willard.