The common term “fish eye” refers to a plantar wart (verruca plantaris), a frequent, non-cancerous skin growth on the sole of the foot. Plantar warts are caused by a specific viral infection. These growths often cause discomfort because walking pressure forces them inward, making them appear flat and tough. This article details effective removal methods, ranging from accessible at-home treatments to more aggressive clinical procedures.
Understanding the Cause and Appearance
Plantar warts are caused by certain strains of the Human Papillomavirus (HPV), which enters the body through tiny cuts or breaks in the skin on the bottom of the foot. This virus stimulates rapid growth of skin cells, eventually forming the characteristic rough, grainy texture of the wart. The virus thrives in warm, moist environments, and the infection may take several weeks or months to become visible after initial exposure.
The physical appearance is distinct, often presenting as a small, rough patch of skin on the heel or ball of the foot, where pressure is highest. Because of this constant pressure, the wart is pushed inward beneath a layer of hard, thickened skin, which is often mistaken for a common callus. A defining feature is the presence of small, dark pinpoints inside the wart, which are actually tiny clotted blood vessels, not the “eye” or “seed” of the wart itself.
Over-the-Counter and Home Removal Methods
The most widely used treatment involves over-the-counter preparations containing salicylic acid, a keratolytic agent that chemically peels away the infected skin layers. These products are available in concentrations ranging from 17% to 40% and come as liquids, gels, or adhesive patches. The acid also causes mild irritation, which can prompt the body’s immune system to mount a response against the underlying virus.
To maximize effectiveness, the wart should first be soaked in warm water for five to ten minutes to soften the thickened skin. After soaking, the dead, white tissue should be gently removed with a pumice stone or an emery board, taking care not to cause bleeding or share the tool. The salicylic acid product is then applied directly to the wart’s surface, and this entire process is repeated once or twice daily for several weeks.
Another non-prescription option is an over-the-counter cryotherapy kit, which uses freezing agents, such as dimethyl ether and propane, to cool the wart rapidly. This process destroys the wart tissue by freezing it, causing a blister to form underneath that eventually lifts the dead tissue off the skin. These kits are generally less cold and effective than professional liquid nitrogen treatments, but they offer a convenient first step for minor growths.
A well-known home remedy is duct tape occlusion, where the wart is covered with silver duct tape and changed every few days. While some studies suggest a potential benefit, the scientific evidence remains mixed, and the exact mechanism is not fully understood. Individuals with underlying conditions, such as diabetes, poor circulation, or numbness in their feet, should avoid self-treating and seek professional care immediately to prevent complications.
Clinical Procedures for Stubborn Warts
When home treatments fail to clear the growth, a dermatologist or podiatrist can offer stronger, in-office procedures for persistent warts. Clinical cryotherapy involves the precise application of liquid nitrogen, which reaches a much colder temperature than OTC kits. This intense cold rapidly freezes and destroys the wart tissue, often requiring multiple sessions spaced two to four weeks apart to fully resolve the lesion.
Another physician-applied chemical treatment uses cantharidin, a blistering agent. The doctor applies the solution to the pared wart and covers it, allowing a blister to form within 24 hours. This blister helps lift the wart off the skin, and the dead tissue is removed after about one week.
For large, painful, or highly resistant warts, more aggressive methods may be necessary, such as minor surgery or laser treatment. Surgical curettage involves cutting away the wart tissue, often combined with electrocautery to burn the base and minimize recurrence. Alternatively, pulsed-dye laser treatment targets the tiny blood vessels supplying the wart, causing the infected tissue to die and fall off. Because scarring can be painful on the weight-bearing sole of the foot, these procedures are reserved for cases where all other treatments have been unsuccessful.
Strategies for Preventing Future Warts
Preventing plantar warts centers on minimizing the risk of HPV exposure and maintaining good foot hygiene. Since the virus thrives in warm, moist environments, it is highly recommended to wear protective footwear in public areas. Wearing flip-flops or sandals in communal showers, locker rooms, and around public pools can significantly reduce direct contact with contaminated surfaces.
Maintaining dry and healthy skin on the feet creates a less hospitable environment for the virus. This includes washing the feet daily and drying them thoroughly, particularly between the toes. Using moisture-wicking socks and allowing shoes to air out can help prevent the damp conditions that promote viral entry.
The HPV virus is contagious through direct and indirect contact, so avoiding the sharing of personal items is a straightforward preventative measure. Items that can harbor the virus should not be shared:
- Towels
- Socks
- Shoes
- Nail clippers
Promptly covering any existing warts with a bandage also helps prevent the spread of the virus to other parts of the body or to other people.