Nail fungus is called a mycosis and the reason it is the spores of a parasitic fungus. Ill any person, just simple contact with a person who has the fungus. The risk of catching a fungus high in the saunas, baths, water parks, on beaches or in the pool.
The fungus commonly affects the nails and therefore of what kind of doctor treats fungus toenails have to think a lot of people. In the part of skin pathologies a generalist is a doctor-dermatologist.