Verrucas, technically known as plantar warts, are common skin lesions found on the soles of the feet, caused by an infection with the human papillomavirus (HPV). They develop when the virus enters the skin through tiny cuts or abrasions, leading to an overgrowth of skin cells. While many verrucas are small and painless, those that cause discomfort often prompt people to seek treatment. The reason some verrucas are painful is directly related to their location and unique growth pattern.
Identifying Verrucas
A verruca is a type of wart that typically appears as a small, rough, and grainy patch of skin on the weight-bearing surfaces of the foot. They frequently develop on the heel or the ball of the foot, which are areas subjected to the most pressure.
A distinguishing feature that helps differentiate a verruca from a common callus or corn is the presence of minute, dark pinpoints within the lesion. These specks are tiny, clotted blood vessels, known as thrombosed capillaries, which are a direct result of the viral infection. Another way to identify a verruca is through the “squeeze test,” as pain is often elicited when the lesion is pinched from the sides, which contrasts with a callus that usually hurts more from direct pressure. The pattern of skin lines, or dermatoglyphics, also becomes disrupted around the verruca, whereas these lines simply pass through a corn or callus.
The Mechanics of Verruca Pain
The primary reason a verruca causes pain is mechanical, stemming from its inverted growth pattern in a high-pressure environment. Unlike warts on the hands, which tend to grow outward, verrucas are forced inward by the constant pressure of body weight. This downward growth pushes the lesion into the deeper layers of the foot tissue, specifically into the dermis.
The dermis contains numerous sensitive nerve endings, and the inward-growing verruca presses against these nerves with every step, leading to sharp, localized pain often described as feeling like stepping on a needle. The severity of the pain is directly related to two factors: the depth of the lesion’s growth and its location on a major weight-bearing area.
Additionally, the body often reacts to the verruca by forming a layer of hard, protective skin, or callus, over the top. This layer of thickened skin compounds the issue by increasing the downward pressure on the already irritated nerve tissue underneath.
Standard Treatment Approaches
Standard treatment approaches aim to destroy the infected tissue and stimulate the body’s immune system to clear the virus. Over-the-counter and prescription treatments commonly utilize a strong concentration of salicylic acid, which works as a chemical exfoliant. The acid softens and dissolves the layers of the verruca, allowing for better penetration into the core of the lesion.
Another widely available option is cryotherapy, which involves freezing the verruca, often with liquid nitrogen, to destroy the tissue through extreme cold. This process causes a blister to form underneath the lesion, which eventually lifts the dead viral tissue away from the healthy skin below. While both salicylic acid and cryotherapy have similar, modest success rates when used alone, they are often combined, as this dual approach can be more effective at eradicating the verruca.
For lesions that are large, persistent, or causing severe pain, professional intervention may be necessary. A healthcare provider, such as a podiatrist, can offer stronger prescription-strength treatments or in-office procedures. These advanced options may include specialized needling techniques to stimulate the immune response directly, or surgical excision for deeply rooted or treatment-resistant verrucas.