What Causes Gray Nails?

My toenails initially turned slightly white, then gradually began to detach, becoming uneven and irregular. After searching online, I discovered these are typical symptoms of onychomycosis (commonly known as “ringworm of the nail”). So, what causes onychomycosis?

What Causes Onychomycosis?

Onychomycosis often develops when a pre-existing tinea infection (e.g., tinea manuum—hand fungus) spreads and the causative fungi continue to proliferate, eventually invading the fingernails or toenails. Fungal infection can damage the nail plate. Early signs typically include nail plate cloudiness or loss of luster, followed by softening and brittleness of the nail. In some cases, nail plate thickening or a powdery appearance along the free edge may occur—these are hallmark features of onychomycosis. Additionally, trauma to the nail may predispose it to secondary fungal infection. Direct fungal invasion of the nail plate leads to structural damage, resulting in the characteristic grayish discoloration.

When managing onychomycosis, wear gloves during household chores or other activities to prevent water contact with infected nails. Water exposure causes infected nails to swell and subsequently shrink upon drying, further damaging the nail structure. Avoid alkaline cleaning agents such as hand soap, laundry detergent, or bar soap, as they readily compromise the skin’s natural barrier function. Do not cut or trim the cuticles (the hardened skin alongside the nail edges), as this increases the risk of skin injury and subsequent paronychia (nail fold infection). Also, avoid cutting nails too short, which may traumatize the periungual tissue and trigger inflammation.

Preventive measures include enhancing immune resistance and maintaining dryness—especially of the feet—through appropriate physical activity. Fungal infections are more common among individuals with severe systemic illnesses, compromised immunity, excessive physical exertion, prolonged use of immunosuppressive agents (e.g., corticosteroids), or those who have undergone organ transplantation. We hope this information proves helpful!