Your son has a plantar wart on his foot. This is a common skin infection caused by human papillomavirus (HPV). There are many strains of HPV. You may have heard that HPV is the cause of cervical cancer and several other cancers in women and in men. The strains that cause cancer are different from the strains that cause plantar warts. There are other warts around the genitalia that are caused by yet other strains of HPV, so please don’t get them confused.

Plantar warts are spread from person to person, most likely when we walk on our barefeet, especially over wet surfaces around the pool and in changing rooms. He can still go to the pool if he puts on a pair of slippers as soon as he takes off his socks in the changing room, and keeps them on until he sits down at the pool side. In this way, his feet will not touch the ground, and he will not spread the virus. Pools are chlorinated; the virus cannot survive in the water.

Plantar warts are mostly benign, except that they cause pain and discomfort when we walk and run. Well-cushioned sneakers can absorb some of the pressure, and reduce the pain somewhat. Left alone, warts can go away after months to years; these are painful years! Sooner or later, our body’s immune system will recognize the infection, and mount an immune response to get rid of the virus and the warts. Plantar warts, like other warts on our hands and body, have the unique ability to infect only the uppermost cells of our skin, therefore, avoid being detected by our immune system.

Over the millennia, humans have tried to remove warts by cutting them, rubbing them with stone. None of these work too well. Salicylic acid has been used for decades. It works partly by removing some of the infected cells, and partly (this is speculation) by triggering the body’s immune cells to get rid of the infection. This is a long process, and not always effective. Some have used duct tapes with variable results.

Physicians have few other tools to get rid of plantar warts (as well as warts on the hand). Freezing these warts with liquid nitrogen does work, but it is painful and requires multiple treatments. Most of the time, a blister will form around the wart. Another procedure is to “burn” the wart with an equipment called cauterizer, and scoop away the infected cells. This is also a painful procedure and requires injection of local anaesthesia.

A medicine called imiquimod (Aldara) was approved for treatment of genital warts over a decade ago. It is available as a cream that can be applied on and around the wart. It is regarded as an immune response modifier, attracting our body’s immune cells to the wart and killing the virus over time. This process often takes several weeks.

Although Aldara cream is approved for genital warts, physicians have used it successfully in treating plantar warts as well. Some physicians recommend covering the infected area with duct tape after applying the cream once a day or every second day. If there is inflammation around the wart, reduce the frequency of application. Otherwise there is no significant side effect.

I hope this is helpful when you discuss different treatment options with your physician.