Strep is on the rise, and experts are concerned that the potentially deadly illness is presenting with some atypical symptoms.

“I’ve been in infectious diseases and pediatrics for 30 years and I’ve never seen it this bad,” Dr. Greg DeMuri, a pediatric infectious disease expert with UW Health Kids in Madison, Wisconsin tells TODAY.com. “We are at a level twice that of our worst year, looking back over the past 10, 20 years or so.”

Strep throat is caused by the bacteria Group A streptococcus and is common in children and teens any time of the year. It usually peaks between December and April. But this year it’s worse. In fact, Illinois has seen five pediatric deaths this year due to strep. Providers are reporting that patients are presenting with mild or atypical symptoms, making it more difficult to diagnose the highly infectious disease.

The usual complaints are a sore or scratchy throat, pain when swallowing, red or swollen tonsils, headaches, and body aches. The infection is spread between people through respiratory droplets, says TODAY.com. While it normally affects kids between five to 15 years of age, DeMuri says he is seeing a strep surge in toddlers and infants.

Sometimes the strep bacteria can spread into the bloodstream. This is called invasive strep, and recently the Centers for Disease Control and Prevention (CDC) issued an alert about the resurgence after two children died. DeMuri says the number of invasive strep cases is “disturbing.”

Experts say that the masking and social distancing practices during the pandemic have helped trigger this rise in strep. Now that children are being exposed to viruses and bacteria, infections are surging to pre-pandemic levels — and worse.

“All the really bad manifestations of strep are really popping up,” notes DeMuri.

Early testing and treatment are key. Testing is relatively easy but requires a healthcare provider to administer. You can get a rapid strep test in your doctor’s office, as well as strep culture if this is negative. There is also a strep PCR swab that is fast and accurate, but not all medical offices have them, says TODAY.com.  Strep is treated with antibiotics such as penicillin or amoxicillin, say experts, but may need a second-line drug.

You should get tested for strep if you have:

• Classic symptoms of strep, especially a fever, for 24 hours.

• Cold-like symptoms that are not improving or getting worse

• Been exposed to strep by family members, friends, or classmates.

“The point is, if someone has a runny nose or a cough, that doesn’t mean its NOT strep. It is still something to look into and maybe do a test to see if it’s strep throat or not,” says Dr. Alin Abraham, a pediatrician at Northwestern Medicine Central DuPage Hospital. If a child does test positive for strep, they can go back to school and resume activities 24 hours after they start antibiotics and are fever-free, says Abraham. Without antibiotics, a person may be contagious for two weeks.