Strep throat often presents atypically in young children. Sometimes, the only symptom that I will get is some vague abdominal pain. Other common symptoms such as fever, sore throat, or headache are frequently absent. On exam, the abdomen is benign and the throat may only be mildly inflamed. For these kids, I usually check a rapid Strep test and send a throat culture to the lab. I have been surprised many times!
Obviously, a urinary tract infection is also in the differential.