Does the fungus that causes gray nail (onychomycosis) cause cancer?

Onychomycosis, also known as tinea unguium, is primarily caused by fungi such as dermatophytes, yeasts, or non-dermatophyte molds. Although these fungi are infectious, they do not directly cause cancer. During their growth, some fungi may produce certain toxins—such as aflatoxin B1—that could potentially be carcinogenic under specific circumstances. However, this risk is not directly related to onychomycosis itself, but rather to the metabolic products of fungi in particular environments. While the fungi responsible for onychomycosis do not directly lead to cancer, patients should still maintain good personal hygiene and avoid sharing personal items with others to prevent cross-infection. Additionally, when necessary, appropriate treatments should be used under medical supervision to control the condition and prevent recurrence.