Empty toenails are often associated with microbial infections and may be a symptom of some infectious diseases such as onychomycosis and nail fungus. Small traumas around the nail, manicure and other factors can easily lead to skin damage and thus microbial infection. The main clinical symptoms of patients with onychomycosis are redness, swelling, fever and pain in the perinail tissues, and in severe cases, it can lead to abscess, pus flowing out of the nail grooves, and the nail plate being destroyed, etc. Therefore, a defective toenail can be seen from the appearance and accompanied by a foul odor. As a result, toenail defects can be seen externally and can be accompanied by a foul odor. Candida, dermatophytes, yeasts and molds can cause lesions on the nail plate as well as under the nail leading to nail fungus. Patients may exhibit symptoms such as nail plate atrophy, brittleness, nail plate loss, and pain. When patients experience discomfort, they should go to the hospital immediately.