Hi Ada, all the information you are looking for is on the CVSA web page. Under the research tab you can read the testing guidelines for children, with many tests symptom suggestions. You will also find the Empiric Guidelines which I still find helpful. The suggestions for supplements, with doctor approval, are also posted there.
For doctors in Europe, there are links to different countries on the CVSA web page. Many countries now have a CVSA group or liaison who will have the information on doctors.
You can also email the CVSA office and see if Debbie has information on European MDs. It might be worth the extra travel to get to the US. Your home country doctor and the US doctor can consult on testing and medication protocal.
You can reach Debbie at firstname.lastname@example.org
Good luck. It is very difficult to see your child suffer from this condition. Most do get much better.