Ciao

Can anyone tell me if existing medical conditions are covered by swiss health insurance schemes?

Thanks

No need to worry about that, except if you want private/additional insurance.

Essentially, there is a basic catalogue of coverage that has to be given to everyone and quite rightly, as insurance is obligatory for all. This does not include homoeopathy and suchlike, but many insurances offer a fairly cheap additional option, I don't know if that option is subject to provisos though.