A verruca is the technical medical term for a common skin growth resulting from a benign, uncontrolled proliferation of skin cells in the outer layers. This condition involves the hypertrophy (enlargement) of the papillae and the epidermis (the outermost layer).
The Everyday Term for a Verruca
The common name for a verruca is a wart. The term “verruca” remains the preferred clinical term, especially for warts on the foot, which are called plantar verrucae or Verruca Plantaris. This skin abnormality is characterized by an overgrowth of the epidermis and the dermal papillae, resulting in a raised, often rough growth of excess skin cells.
This overgrowth means the cells in these skin structures have grown larger and increased in number, leading to the characteristic bump. This localized disruption of normal skin architecture is usually not harmful. The common wart (Verruca Vulgaris) is the most frequent presentation of this type of lesion.
The Viral Source and How They Spread
Verrucae are caused exclusively by infection with the Human Papillomavirus (HPV). This virus is common, with over 100 different types, and only specific strains cause typical skin warts. The virus invades the skin through tiny cuts or abrasions, serving as entry points to the epidermis. Once inside, the virus causes skin cells to multiply rapidly and form the visible, hardened lesion.
Warts are contagious and spread through direct skin-to-skin contact or by touching contaminated surfaces. Warm and damp public areas, such as communal showers and pool decks, are frequent sites of transmission for plantar verrucae. The virus can also spread from one area of a person’s body to another (autoinoculation). The incubation period between infection and the appearance of the growth can be long, sometimes taking several months.
Categorizing the Different Types
Verrucae are classified based on their appearance and location, with each type caused by slightly different strains of HPV. Common Warts (Verruca Vulgaris) are the most familiar, appearing as rough, raised, dome-shaped growths, often on the fingers, hands, and knees. They may contain tiny black dots, which are clotted blood vessels.
Plantar Warts (Verruca Plantaris) develop on the soles of the feet. Pressure from walking causes them to grow inward rather than outward, making them painful, and they often have small black specks due to ruptured capillaries. Flat Warts (Verruca Plana) are smaller and smoother than common warts, appearing as slightly raised, flesh-colored or light brown lesions. These frequently occur in clusters on the face, neck, or back of the hands and are often spread by shaving.
Filiform Warts are long, thin, thread-like projections that usually appear on the face, particularly near the lips and eyes. Mosaic Warts are closely clustered groups of plantar warts that grow in a tile-like pattern, typically on the soles of the feet or palms of the hands.
Options for Removal
Verrucae are often harmless and many resolve spontaneously as the body’s immune system eventually clears the virus, but treatment is common for comfort or cosmetic reasons. Over-the-counter (OTC) options primarily rely on topical chemicals to chemically destroy the infected tissue. Salicylic acid is the most common home treatment, applied daily to gradually peel away layers of the wart. This process can take several weeks or months to be effective, and the wart’s surface should be gently filed before each application.
For more rapid results, many people try OTC freezing kits, which use a blend of refrigerants to cool and destroy the wart tissue. These kits mimic the professional procedure of cryotherapy but use less intense temperatures. If OTC remedies fail, or if the wart is large, painful, or located in a sensitive area like the face or genitals, professional intervention is necessary.
Dermatologists offer several in-office treatments that are typically more potent. Cryotherapy involves the precise application of liquid nitrogen, which is extremely cold and instantly freezes the wart, causing the infected tissue to blister and eventually fall off. This method often requires multiple sessions spaced a week or more apart. Other procedures include electrocautery, which uses an electrical current to burn the wart tissue off, and laser treatment, which targets and destroys the blood vessels feeding the wart.
The physician may also prescribe stronger topical medications or use immunotherapy agents to stimulate the patient’s own immune system to fight the virus. For stubborn warts, particularly deeply embedded plantar warts, surgical removal, or curettage, may be performed under local anesthetic to physically scrape the lesion away. The choice of treatment is often tailored to the wart’s size, type, location, and the patient’s age and overall health.