Multiple choice general knowledge Nail fungus is commonly caused by the fungus that causes the ringworm True False Reveal answer Fill a bubble to check yourself A Correct answer Explanation Nail fungus and ringworm are both caused by dermatophytes, a group of fungi that infect keratinized tissues like skin, hair, and nails. The same fungi (such as Trichophyton) that cause ringworm (tinea corporis) can also infect nails (onychomycosis).