fear of undressing for doctor appointments

When I was a child I was sexually abused and as a result I have a fear of undressing in medical settings for doctor appointments. As much as possible, I avoid male physicians (even though I am a male), seeking instead to utilize female physicians. There have been times that I have not made appointments for yearly checkups or cancelled them out of fear and nervousness. Because of a pre-cancerous skin condition, I do have to go through a yearly complete skin check six months after my yearly physical. I have tried various things, such as getting undressed from my regular clothes, being in a gown, my underwear, or just covered by a sheet. My anxiety over getting undressed is worse than actually being undressed. Once I am as undressed as I'm going to be, I feel like the worst part is behind me and I can start settling down inside. Does anyone have any ideas on how to overcome this fear and how to make appointments easier?