In briefActive people often seek medical care for discoloration and deterioration of toenails or fingernails. The problem may be a fungal infection of the nail (onychomycosis). Microscopic examination often shows strong evidence of onychomycosis, but a fungal culture will confirm the diagnosis. Antifungal medication alone or with conservative avulsion may resolve the fungal infection. If not, surgical nail removal may be needed for resistant cases.