Bite-sized advice for busy GPs
Warts are caused by the human papilloma virus with numerous genotypes, 77 at the last count.
Once warts were thought to be associated with atopic eczema, but this is now known not to be the case. Warts are associated with immunosuppression, so are common in transplants.
Warts are common in children, occurring at sites of trauma. Approximately 70 per cent have common warts and 24 per cent have verrucae. The rest have plane warts, filiform warts and anogenital warts.
Patients with warts need time to develop an immune response. If left untreated they resolve without scarring. Two-thirds resolve within two years. Often the pressure to treat originates more from the parents than the child.
Topical salicylic acid is an effective, evidence-based treatment. The wart first needs to be softened in warm water then pared down, before salicylic acid is applied. Salicylic acid should not be used on the face.
Cryotherapy is commonly used, especially for facial warts and resistant common warts. More frequent treatments can speed resolution but do not improve cure rates. Cryotherapy can cause pain and blistering. The more aggressive cryotherapy is, the more likely side-effects are.
A solitary wart in an older patient can cause diagnostic difficulty; the differential diagnosis includes an actinic keratosis or a squamous cell carcinoma. Curette and cautery under local anaesthetic not only provides a cure but
also a histological diagnosis.
Duct tape has been put forward as a simple, non-traumatic therapy. The theory is that irritation stimulates the immune system. A piece of tape is applied for six days then removed, the wart soaked in water then scraped with a pumice stone. This process is repeated every 12 hours until it goes.
Modern methods of treatment include photodynamic therapy and vaporisation with lasers. These are expensive and not routinely available on the NHS. Others include bleomycin injections and topical immune modulators such as imiquimod.
Alternative therapies include homoeopathy and hypnosis. While not scientifically proven, they give nature a chance and probably do little harm, except to the pocket. Belief in these therapies seems to improve efficacy. Topical herbal remedies include oregano oil and the juice of dandelion.
Folklore treatments include rubbing the warts two days after a full moon with bacon or a potato and burying it. One can pass warts on by placing as many beans as you have warts in a bag and placing it at the intersection of two roads. Whoever picks it up gets the warts.
Thomas Poyner is a GP and hospital practitioner in Stockton-on-Tees