Onychomycosis: Symptoms, Causes & Treatment

Nail fungus is a common fungal infection affecting the nails, affecting the toenails much more than the fingernails, because the foot's environment inside the shoe (warmth, moisture, and darkness) is ideal for fungal growth. The infection usually begins at the tip or side of the nail then spreads slowly toward the root, and may affect one nail or several nails. It is often associated with a fungal infection of the foot's skin (athlete's foot) that spreads to the nail.

The symptoms of nail fungus develop gradually over months and include: a change in the nail's color (to yellow, brown, or white), increased thickness, distortion of its shape, crumbling and breaking at the edges, sometimes its separation from its base, and it may be accompanied by an unpleasant odor. It is usually not painful at first, but as it progresses it may cause discomfort or pain when walking or wearing shoes. The chances of developing it increase with age, diabetes, poor foot circulation, excessive sweating, walking barefoot in humid public places (such as pools and bathrooms), nail injuries, and weak immunity.

Nail fungus is among the relatively stubborn conditions to treat, because the nail grows slowly and the fungus is deep inside it, so treatment requires patience and commitment for a long period that may extend months. Treatment depends on the severity and the number of affected nails: in mild cases an antifungal lacquer or solution applied to the nail regularly may suffice, while more severe cases or multiple nails need an oral antifungal determined by the doctor for a specific period (with monitoring that may include liver function). It is important to confirm the diagnosis before treatment because the nail's appearance may resemble other conditions. Even after healing, the infection may return, so prevention is important: drying the feet well, wearing suitable socks and shoes, avoiding walking barefoot in humid public places, treating athlete's foot, and not sharing nail-clipping tools.

• A change in the nail's color (yellow, brown, or white).
• Increased thickness, distortion of shape, crumbling, and breaking.
• Sometimes separation from its base and an unpleasant odor.
• Usually painless at first, may hurt later when walking.

• A fungal infection affecting the nail, more in the toes (warmth and moisture in the shoe).
• Often associated with athlete's foot.
• Risk factors: age, diabetes, poor circulation, sweating, walking barefoot in public places.

• Clinical diagnosis from the nail's appearance.
• Taking a nail sample for laboratory examination to confirm the fungus (important before oral treatment).
• Distinguishing from other conditions resembling nail fungus.

Mild cases

• An antifungal lacquer or solution applied to the nail regularly.

More severe cases or multiple nails

• An oral antifungal determined by the doctor for a specific period (with monitoring that may include liver function).

Treatment requires patience and commitment for months because the nail grows slowly. This content is educational and does not replace consulting a dermatologist.

• Spread of infection to other nails or to the foot's skin.
• Pain and difficulty walking as it progresses.
• A deeper infection in diabetic and immunocompromised patients.

• Drying the feet well and wearing suitable socks and shoes.
• Avoiding walking barefoot in humid public places, and treating athlete's foot.
• Not sharing nail-clipping tools, and foot care especially for diabetic patients.