Tremendous troubles with spouse who picks

Greetings one and all. I don't know if this will be helpful or not, or even if this is the right place for this, but at this point I'm up for trying anything. My wife is the one with the problem, although it is to the point where it is, I fear, slowly destroying our marriage. So it does affect me in a co-dependent way I guess. The main problem with her is she will not acknowledge or admit that she is doing this to herself. She is in her early 60s and has been doing this for a long time-years in fact. She is adamant and insistent that she has some kind of "infection" in her body that has to "come out" and so when it does "come out" her skin erupts in lesions and sores. As far as I can tell, she helps it out by rubbing and digging at her skin where she thinks this infection is. She has literally made of mess of her body where this happens–her face, her arms, torso, her legs and feet, pretty much all over. This has been going on for a long time and I've tried to be as supportive with her as I can, but it tests me, that's for sure. She is skeptical of doctors because she thinks they mis-diagnose her when they can't confirm her infection theory. She is certain she knows what she has, and if a medical professional doesn't see it her way, she discounts them. That of course, makes it difficult to treat. Anti-depressants have helped her in the past, but she has been off of them for a while because she could not get a Rx refill because she stopped going to the doctor who was prescribing them for her. I have finally gotten her to agree to go see a new doctor next week at the clinic where I go for my primary care. I'm hopeful this will be a step in the right direction, although I fear that without some psychological intervention, progress will be difficult. And since she is so adamant that there is nothing psychological involved in her condition, it will be hard to get her the help she needs. From what I've seen on the web, the terms "psychogenic excoriation" and "dermatitis artefacta" best describe what is happening with her. I'm really starting to question how much longer I can deal with this, but certainly don't see any easy way out. Thanks for listening. Any input would be greatly appreciated.