Cryotherapy using Liquid Nitrogen @ -196°C is used for treatment against stubborn warts

What is a wart?

Verruca vulgaris, also known as the common wart, is a benign growth caused by many types of human papillomavirus (HPV). Warts are very common in children and adolescents, but are seen across all age groups. Common sites affected are the feet, hands, face, and also the genitals. HPV is spread by direct physical contact with an infected surface. You can be infected by another person, your own touch if you have HPV on another site of your body, or sharing objects such as towels, razors, socks, and slippers. After being infected with HPV, it can take many months of slow growth before you can notice a wart. Some warts can be painful when pressure is applied.

Treatment

Most warts do not need treatment. They generally regress over a few months as your own immune system deals with them. However, when warts are painful or spreading, or when you’re bothered by how they look, you have several treatment options.

  • Keratolytic agents: these are medications that cause the thickened warty skin to swell, soften, and peel off. Topical salicylic acid is a common example of such medications.
  • Injections: stronger medications like BCG vaccine injections into the warty growth is used sometimes.
  • Cryotherapy: using liquid nitrogen (at -196 degrees Celcius) to freeze the wart.
  • Minor surgery: electrosurgery, curettage, laser surgery can be used to surgically remove the wart.

Wart treatment does not always work. This is because the treatment may remove the wart, but some residual virus may still persist. This residual virus would need to be eradicated by your immune system. In some cases, the wart can recur and you may need to undergo therapy again.

Cryotherapy

We employ liquid nitrogen therapy in our Punggol MRT clinic. It is administered by a doctor. Sometimes, the doctor will use a razor to pare or thin the cornified skin before using the liquid nitrogen. Liquid nitrogen is applied via a spray gun or a Q-tip. The idea is to create a ball of ice around the wart to destroy the wart and induce inflammation to allow healing. The doctor may apply liquid nitrogen for 2 or 3 cycles, allowing the frozen tissue to thaw in between.

The process may cause some discomfort due to the cold temperature. You may feel numb, or poking pain during the freezing. A couple of days after the session, some patients develop a mild throbbing pain or blister at the site. The pain can be controlled with simple analgesia like paracetamol or ibuprofen. After 3-7 days, the wart may drop off entirely or shrink in size. You may require more than 1 session. Subsequent sessions are done between 2 to 4 weeks interval.