Nail Fungus (Onychomycosis): Symptoms, Causes, Treatment & Prevention

Nail Fungus Nail Fungus (Onychomycosis): Symptoms, Causes, Treatment & Prevention Nail fungus, also called onychomycosis, is a fungal infection that can affect fingernails or toenails. It often causes discoloration, thickening, brittleness, crumbling, or lifting of the nail, but other nail conditions can look similar. Published by Healthy Nail Institute • Updated July 27, 2026 Quick […]