Which nail disease is not caused by fungus?

• A. Paronychia
• B. Onychomycosis
• C. Tinea unguium
• D. Dermatophytosis

Answer: (A)

Understanding nail infections helps differentiate their causes. Onychomycosis, also called tinea unguium, is a fungal infection of the nail plate caused by dermatophytes or other fungi. Dermatophytosis refers to fungal infections caused by dermatophytes and can involve the nails as part of the same fungal process. Paronychia, however, is an infection and inflammation of the nail folds surrounding the nail. It is most commonly caused by bacteria such as Staphylococcus aureus or Streptococcus species in acute cases, with fungal causes (like Candida) occurring mainly in chronic situations. So the nail condition described as not being caused by fungus is paronychia, since the others are fungal infections.