Which of the following is a common nail disease?

Onychomycosis is a prevalent nail disease that specifically refers to a fungal infection of the nails. It is characterized by changes such as thickening, discoloration, and eventual degradation of the nail structure. This condition highlights the susceptibility of nails to fungal pathogens, which can thrive in warm, moist environments commonly found in areas such as public showers, swimming pools, and poorly ventilated shoes.

Understanding onychomycosis is crucial for nail technicians, as recognition of the symptoms and proper hygiene practices are essential to prevent its spread. While psoriasis and fungal infections are related to skin and nails, they do not exclusively describe a nail disease like onychomycosis does. Acne, on the other hand, primarily affects the skin and does not pertain to nail health at all. Therefore, onychomycosis stands out as the specific nail disease in the given options.