How can i know whether my 2 yr old boy infected sore throat as he suddenly lost his appetide.?

May need evaluation: As a two year old may not be able to tell you specific issues, it can be hard. Losing appetite can be a sign of illness in a child, and a sore throat can cause that. If he is able to keep fluid down, and is not acting too sick, and has no trouble breathing, he will likely get better in a few days. If he looks or acts very sick, drools, can't keep fluid down and so on he should be checked out.

Fever,odor,drooling: Many common viral infections cause sore throat and appetite loss. If there is a runny nose and cough you will probably not get an antibiotic when you see the doc. Two year old children get strep throat rarely. Signs of strep throat are sudden onset of fever, sore throat, headache and swollen glands. Does he have all his vaccines? If so rare causes of throat infection are unlikley. Viruses=common.

Suggestive signs: Any febrile illness can suppress appetite. If sore throat is truly a cause, abnormal physical finding should be present. However, good inspection of young child's throat is not an easy task for the lay people. Drooling and swollen gland under jaw bone in a febrile child would be helpful hints.