Why do so many doctors treat symptoms and causes? e.g. had neck rash so pcp prescribes steroid cream// cause:sertraline solution: get off sertraline

Medicine is complex: Medicine is complex, and a diagnosis is always an educated guess. Symptoms and the environment they arise in are clues to what is (or is not) wrong, but there are many possible causes to any symptom. Drug rashes rarely appear on the neck alone where contact dermatitis often does, the timing of the rash might have been a clue that it was a drug reaction, but it would have been a stretch.