What are warts — and how do you get rid of them?

Throughout history, various remedies and superstitions have been proposed to explain the origins of warts. People believed that warts were caused by contact with things such as sea foam, boiled egg water, and notably, toads. The idea that toads were involved in the formation of warts is now known to be a misconception. In reality, toads are completely innocent of this affliction. The warty appearance of toads is due to their skin's mucus-secreting and poison-secreting glands, not any magical properties.

Today, we understand that warts are caused by a group of viruses known as papillomaviruses. These viruses belong to a broad family that infects various species, including humans. There are over 200 distinct types of human papillomaviruses (HPVs). Like all viruses, HPVs cannot replicate on their own; they rely on the host’s cells for this purpose. Specifically, HPVs infect the basal cells located at the base of the epidermis, which is the outermost layer of our skin. The epidermis is our largest organ and serves as a crucial barrier, protecting the body from various pathogens that constantly threaten to penetrate it.

When HPVs manage to breach the skin’s outer defenses, they face a robust immune response designed to eliminate them. However, HPVs sometimes succeed in penetrating deeper layers of the skin, especially when the skin is compromised—such as when it is wet, softened, or injured. Even minor cuts can increase the likelihood of HPV infection. This is why warts are most commonly found on hands and feet, where the skin is more likely to be exposed to foreign surfaces and minor injuries, particularly in communal and moist environments like locker rooms or swimming pools.

Once HPV infiltrates the basal cell layer, it introduces its genetic material into these cells. This genetic material directs the basal cells to multiply at an accelerated rate, delay their programmed cell death, and produce more viruses. As the infected cells continue to proliferate, they push upwards towards the skin’s surface, resulting in the formation of warts. The appearance of these warts can vary depending on several factors.

Different types of HPV tend to infect specific areas of the body, leading to distinct wart appearances. Common warts, for instance, are often dome-shaped and appear on hands, elbows, and knees. Plantar warts develop on the soles of the feet and may become flattened due to pressure from walking. Filiform warts usually appear around the mouth and eyes, while flat warts are typically found on the legs and face. Some warts may also present with tiny black dots, which are actually small blood clots resulting from blocked capillaries in the skin.

Regardless of their appearance, warts are contagious because they contain a large number of HPV particles. Consequently, one wart can potentially spread the infection to other parts of an individual's body or to other people through direct or indirect contact. The risk of spreading the virus depends on the type of HPV and the area of the body it prefers to infect.

While most HPVs cause benign warts, some are known to affect mucosal epithelia— the moist, soft tissues lining the reproductive, digestive, and respiratory tracts. These mucosal HPVs are commonly associated with sexually transmitted infections (STIs). Although they are often benign, some types of mucosal HPV can be persistent and may lead to cancers. In response to these risks, doctors may recommend topical treatments, surgical procedures, or HPV vaccines to prevent infection by the most dangerous HPV types. Since their introduction in 2006, HPV vaccines have proven to be nearly 100% effective in preventing infections with high-risk HPV strains.

The body's immune system typically keeps HPV infections in check or clears them within a few years. However, some individuals are more susceptible to persistent infections. For instance, people who frequently handle meat and fish may be exposed to specific HPV types. Children and the elderly are thought to be more vulnerable due to their thinner skin and less robust immune systems. Additionally, compromised immunity from conditions such as smoking, chemotherapy, HIV, or genetic factors can make it more difficult for the body to suppress HPV infections.

Although most warts are harmless and resolve without medical intervention, they remain contagious. Dermatologists have a variety of methods to aid in wart removal. Treatments may work by directly stimulating the immune system or by irritating the wart area to provoke an immune response. Common treatments include salicylic acid and cryotherapy, which involve applying substances to the wart to induce an immune reaction.

In summary, while warts have been historically linked to toads and other folklore, we now know that they are caused by human papillomaviruses. With effective treatments and preventive measures like vaccination, managing warts has become more straightforward. There is no need to attribute these common skin growths to toads, as they are entirely unrelated.