There are thousands of varieties of pathogens, however these varieties can be put into categories which makes it easier to manage. For instance nematodes (worms)are one classification and broad spectrum treatment should cover a large swath.
Testing with most doctors only covers a small percentage of pathogens. Lastly, there are pathogens that have not been officially classified as pathogenic.
I would suggest contacting ParaWellness Labs and read his material and bio. He was a military doctor in Vietnam and is very thorough.
The curing of the psoriasis of your girlfriend likely has to do with the immune response she is encountering. Psoriasis is caused by some type of infection. With her current situation, the immune system is being enabled.
I would suggest searching for posts made by mattk3 and ICU, they have extensive information that could be helpful.