Understanding of warts only recent

Press, 30 November 1987, Page 13

Understanding of warts only recent

From

Dr George Honbury

for the Royal New Zealand College off General Practitioners

The television programme, “Cancer Line," made mentioned of warts as a cause of cancer of the cervix, and with the present discussion of that condition and its early detection, it seems timely to review wart virus infection in humans. The “British Medical Journal,” of October 25, 1986, carried an editorial on the subject: warts are old, but, Mary H. Bunney writes, “The infectious nature of warts was discovered at the end of the last century and the cause, the human papilloma virus, identified in 1950, but only in the last two decades have real advances been made in understanding wart behaviour.” There are many wart viruses, and each appears to cause a different type of wart on the skin. Deep, painful warts on the palms or soles are caused by human papilloma virus 1 (HPVI), common warts HPV2, mosaic warts HPV2, plane warts HPV3, punctate palm and sole warts HPV4, genital warts HPV6, 11, 16, 18 — these last may appear in the throats of babies whose mothers have had genital warts at delivery. Infection happens when infected skinflakes from another part of the body, or from another infected person enter through breaks in the skin. Fresh infected flakes left on warm moist towels or floors may cause infection, although the virus does not seem to survive for long outside the body. Like most virus infections, warts may disappear without treatment, probably as a result of antibody formation in the body — they may simply shrink away, or they may swell and become inflamed, or they may degenerate after haemorrhage into the wart. This spontaneous re-

gression may begin after three months to five years and is complete in three or four weeks — it is very variable, and the time depends on the type and amount of HPV present, and also on the person’s immune state. Those with impaired immunity may suffer from widespread and resistant warts, the worst affected being those taking immunosuppressive drugs, as after organ transplantation, when the common wart may become a serious disability. Treatments must be compared with the rate of spontaneous disappearance. About 20 per cent of people lose their warts after three months, but application of wart paints, if done properly, will cure 70 to 80 per cent of common warts. Freezing with liquid nitrogen or carbon dioxide is faster, but is painful and not popular with small children. Electrical cautery may be used. Surgery leaves scars. Persistant warts may pose a difficult problem, with repeated treatments over many months. Warts around the anus or genitals may be treated with a podophyllin paint (though not during pregnancy as the baby may be damaged) or by freezing. There are other treatments but these seem the most successful. They tend to recur, perhaps because of reinfection by

a sexual partner, so both partners should be treated at once. There are some promising new approaches to wart treatment Various antivirus drugs have been tried, locally by injection into the wart or application as a cream, and by medication. Side effects limit widespread use, though local injection of a substance called bleomycin sulphate has proved very successful, and has been approved as a treatment in Canada. Does wart virus cause cancer? Some HPVs are involved in cancer causation, though not the types commonly found in skin warts. There is a good deal of anxiety about the finding of HPVI6 and 18 in cancers of both male and female genitals, especially of the cervix, but their exact role in the cause of these cancers is far from clear. They may be initiators or activators of the cancers, but many other factors are also important, and certainly not everyone who carries these viruses will develop cancer.

Family Doctor