What Causes Gray Nails?

My toenails initially turned slightly white, then gradually fell off entirely, becoming uneven and irregular in texture. After searching online, I discovered these symptoms match those of onychomycosis (“gray nail”). So, what causes onychomycosis?

What Causes Onychomycosis?

Onychomycosis commonly develops when a pre-existing tinea infection (e.g., tinea manuum) 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.

For individuals with onychomycosis, wearing gloves during household chores or other tasks helps prevent water contact with affected nails. Water exposure causes infected nails to swell and subsequently dry out and shrink, potentially worsening nail damage. 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 at the sides of the nails, as this may cause microtrauma and increase the risk of paronychia. When trimming nails, avoid cutting them too short to prevent injury to the periungual tissue and subsequent inflammation.

Preventive measures include boosting immune resistance and maintaining dryness—especially for the feet—through appropriate physical activity. Fungal infections are more prevalent among individuals with serious underlying medical conditions, compromised immunity, excessive physical exertion, prolonged use of immunosuppressive agents (e.g., corticosteroids), or organ transplantation. We hope this information proves helpful!