What are warts?
Common warts are hard, callous spots and small growths caused by a virus from the family of human papilloma viruses (HPV). The medical name for the common wart is verruca vulgaris. Warts are very common and completely benign.
Who gets warts?
Almost everyone goes through a period of warts on the hands or feet in childhood. The virus spreads through skin-to-skin contact, especially when a wart has been scratched open, allowing the virus to escape more easily. In this way other people become infected, or other parts of the “patient’s” own skin become infected. Adults who had warts as a child will usually not develop them again on re-exposure, because they have built up immunity to the virus. People who take medicines that lower resistance for a long time (for example after an organ transplant) can develop warts again.
How long do warts last?
In 80% of people the warts have completely disappeared within one year, even without any treatment. In 20% of people, however, it takes longer — sometimes many years — before all the warts are gone.
How can warts be treated?
No treatment. Not treating is often the best option. Warts eventually all disappear on their own, and treatment is sometimes more painful and disabling than the warts themselves. Treatment is warranted, however, if there is pain on walking (plantar warts), or so many warts on the fingers that people become very embarrassed or are hindered in working with their hands.
- Topical drops or ointment. Many local agents are used; the most common are salicylic acid in petroleum jelly (salicylic acid softens the wart — protect the surrounding skin with petroleum jelly, then cut away the softened callus with a blade), and application fluids containing dithranol or salicylic acid. These are usually available without prescription from the pharmacy.
- Liquid nitrogen. The doctor can freeze the wart with liquid nitrogen about once a week; as the cells thaw, they die. A bloody blister can form after treatment.
- Electrocoagulation. The warts are burned away with a kind of electrical device. The wart must first be anaesthetised.
- Curettage. The wart is scraped away with a sharp metal spoon; the base is often then cauterised or treated with liquid nitrogen.
- Laser. The CO2 laser and some other “burning lasers” can burn the wart away (again after local anaesthetic). Treating warts with the pulsed dye laser is more experimental: this laser seals the small blood vessels that supply the wart, so it dies.
- Bleomycin. A chemotherapy agent used for some cancers. For very persistent, treatment-resistant warts in adults it can be injected into the warts with a very fine needle. It is not used in children or during pregnancy.
- Surgery. Cutting warts out (with stitches) is usually not a good option: the operation is often extensive, takes place in a difficult area (hands, feet), and the warts very often come back in the scar.
- Duct tape. When more usual treatments have insufficient effect, warts can be treated with duct tape from any hardware store, following a step-by-step method.
It should be noted that even after treatment the chance of warts returning is high: it is estimated that after any well-performed treatment the chance of recurrence is more than 50%.
When to see a doctor
See a doctor if warts are painful, spreading, very numerous or bothersome, if you are unsure whether a growth really is a wart, or if you have reduced immunity.