It could be Strep. You can get a simple test to find out. See your pediatrician. Untreated strep throat can lead to heart or kidney disease.

Mainly sorethroat, could be present with or without fever and swealling of the throat tissues. Since infections withviruses can look identical to a strep throat a strep test is adviced before antibiotic treatment is established since other sore throats don’t need antibiotic treatmen.

To give you a full explanation of the signs and symptoms, I copied a link from Wikipedia which illustrates that even with all the "classic" signs and symptoms of strep throat, clinical criteria alone are only correct in diagnosis strep throat/tonsillitis 56% of the time.

https://en.wikipedia.org/wiki/Centor_criteria

Most sore throats in this age group are viral in origin. If white patches on tonsillitis, could be secondary strep infection. Have a pediatrician take a look.

Symptoms don't necessarily differentiate between strep and a viral infection. Sometimes, a whitish coating over the tonsil will be a sign of strep, but a culture is really the only way to tell apart.

The symptoms of strep throat and non-strep throat infections can be nearly identical. The best and most reliable way to distinguish them is to have a strep test (something that can be done at any urgent care clinic).