Which of the following statements is not correct about onychomycosis:

• A. Caused by biting the nail
• B. Caused by a fungal infection
• C. Affects nails
• D. Responds to antifungal treatment

Answer: (A)

Onychomycosis is a fungal infection of the nails, typically caused by dermatophytes, yeasts, or molds. The statement that it is caused by biting the nail isn’t correct because the infection results from fungi invading the nail, not from the act of biting. Nail biting can cause trauma and create conditions that help fungi take hold, but it isn’t the root cause. The other facts are true: the problem involves the nails, and antifungal treatment can be effective, though the approach (topical or systemic) and success depend on the severity.