Analysis: Hello, gray nails are contagious and can be a source of infection: the fungus inside the gray nails is invisible to the naked eye and often spreads to the outside world the source of infection of pathogenic fungi. Gray nails can scratch and inoculate the fungus to other parts of the body to occur new ringworm, but also can cause family members and bystanders ringworm. Advice: Guidance: Gray nails affect daily life, but also affect the beauty. It is best for patients to go to regular hospitals for treatment in time to prevent the condition from becoming serious and not well-treated. I wish you a speedy recovery!