Mixed diagnoses – 10 cases (5 of 11)

About 65% of viral warts disappear within 2 years.

The management of viral warts is frustrating for both patient and medical practitioner. Deep plantar warts (myrmecia) are particularly troublesome. They frequently affect weight-bearing sites and are painful to walk on. Treatment is relatively ineffective because of the thickness of the stratum corneum. The patient may be unwilling to wait for natural resolution, but needs to be informed that treatment may fail. Start with inexpensive and safe methods: carefully remove the top layers of the wart using a blade, file or pumice stone. Apply salicylic acid (20-50%) to the wart as paint, gel or paste. Useful preparations include Clear Away Wart Remover, Duofilm and Duofilm Extra Strength gel. Protect surrounding skin from chemical irritation. Cover with an adhesive plaster: occlusion enhances results of topical therapy. Repeat daily, if necessary for several months. Stop treatment for a few days to allow recovery if the salicylic acid causes soreness. Physical destruction using cryotherapy is not generally recommended in a weight-bearing area because it is painful. Electodessication with curettage may take several weeks to heal and cause scarring.A recent Cochrane review concluded that 'there is a considerable lack of evidence on which to base the rational use of the local treatments for common warts. There is certainly evidence that simple topical treatments containing salicylic acid have a therapeutic effect. There is less evidence for the efficacy of cryotherapy and no evidence that it is any more effective than simple topical treatments.' The immune modulating agent imiquimod cream may be effective if applied to abraded warts under occlusion. The best frequency and duration of treatment is under investigation. Other treatments include podophyllin resin (Posalfilin Ointment or Paint), cantharidin (blister beetle extract), dinitrochlorobenzene or dibutyl squaric acid (contact sensitisers), trichloroacetic acid (no longer available from retail pharmacies), topical 5-fluorouracil or intralesional bleomycin (cytotoxics), oral retinoids, intralesional interferons, photodynamic therapy and CO2 laser vaporisation.