I have worked for 6 years for a Derm. and 4 years for 2 different Plastic Surgeon's (as a office coordinator/secretary) and am currently in Esthetician school for my license.
From what I've noticed in the medical offices I worked in, is that:
1. Depending on the doctor, you don't need any special "medical" training, just your esthetic license and some post graduate classes (which could be a one day seminar) on medical esthetics.
Some doctors will have the current esthetician in their office train you.
2. A background in dermatology or plastic surgery terminology is very helpful.
I suggest first trying to get a job in one of these offices as a secretary or receptionist first, to learn the business, terminology, and procedures. If you become friends with the esthetician there, she can help guide you.
3. Remember, these offices are very "appearance" oriented. Getting a position in a Derm and/or Plastic Surgeon's office is a combination of:
A. Being in the right place at the right time. Luck...
B. Knowing an insider in one of these offices
C. Some sales experience will help. The Dr's will want someone who is good at selling services and products.
D. The doctors I have worked with tend to choose employees based on their appearance. For example, they may hire a less qualified individual if this person is a "knockout" appearance wise. Its unfair, but thats how it works in most offices.