Warts are caused by a virus (Human Papilloma Virus or HPV) that has infected the skin. This virus is very common. Probably 75% of people around the world get a wart at one time or another in their lives. 50-65% of warts go away by themselves within 2 years. Unfortunately, we can’t tell which warts will go away by themselves and which ones will not. Sometimes, warts can grow larger and deeper, or can spread to other parts of the skin.
Warts can be treated at home with over-the-counter salicylic acid preparations such as Compound W or Duofilm or Soluver or Dr. Scholl’s. If these fail, or if the warts are large or deep to start with, they can be treated at your doctor’s office with either liquid nitrogen or Cantharone.
Warts can be treated in the doctor’s office by freezing it with liquid nitrogen. Liquid nitrogen is very cold (-196oC). When applied to the wart it kills the infected skin by giving it frostbite. This can be painful. There is a burning pain while the liquid nitrogen is being applied, and a dull throbbing pain later. The longer the liquid nitrogen is applied, the deeper the freezing will go and the faster you’ll improve. It will also hurt more. You can reduce the amount of pain by applying ice to the treated area (hold it for 10 minutes on and 10 minutes off) and by taking Tylenol or ibuprofen (Advil or Motrim). After freezing, a yellow, brown or purple scab may form. This should be left alone. Occasionally, freezing can cause a blister over the wart. This should be left alone unless it is very painful. If so, you can lance the blister (you can sterilize a needle by letting it sit in a dish of rubbing alcohol for 10 minutes). If you do, or if the blister breaks by itself, apply an antibiotic cream to the area twice a day and keep it covered to prevent infection.
Cantharone is a chemical derived from a beetle which causes a chemical “burn” to the skin and can cause a wart to blister and peel. This medicine looks like clear nail polish and has to be applied by a physician. Once dry, it is covered with tape and allowed to remain on the skin for 3-12 hours. It does not hurt when applied. This medicine will make the skin red and swollen overnight and may cause a blister in one or two days. The wart may be sore then. If the blister is very painful, it can be lanced (see above under LIQUID NITROGEN).