Strep throat is diagnosed either by clinical exam or by lab test by swabbing the throat. Strep throat always needs to be treated with antibiotics to prevent cardiac and possible neurological complications later on due to untreated strep throat infection. Strep throat is caused by a bacteria that can lead to Rheumatic fever with severe cardiac complications, which could be prevented by prompt treatment.
Hope this helps.
So the answer to your question is no, "medicine" is not always necessary to "treat" strep infection, but I would consider the prevention of the other conditions in your decision on whether to treat your child with antibiotics.
Rubina Azam MD, FAAP, ABOIM