Is it illegal for a doctor to directly or indirectly lie to a patient?

My wife recently developed lessions on her tongue that resemble the hsv. We went and seen a doctor at the emergency room since it could be a contagious desease and we have 2 kids. The doctor looked at her tongue and said it was definitely a virus that was transmitted by saliva or other body fluids. I thought she was dancing around the truth of the matter so I asked if it was hsv.she responded that there was no way to tell. I asked if there was a test that could be done and she answered no. Since this could be a desease that you definitely wouldnt was your kids to catch and something I really dont want to have. I am angry with the lie since labratory test can confirm it. we have insurance so the test would have been covered. I feel like she lied because it was the kind of information that could end a marriage.