At Toronto Dermatology Centre, we regularly treat patients who have warts, a superficial viral infection (therefore contagious by touch/contact) of the skin caused by the human papilloma virus (HPV). Thankfully, this condition is benign and often self-limited (meaning it can go away on its own even without treatment). Warts can affect skin and mucosa, and there are more than 150 types/strains of this virus. Clinically, HPV manifests itself as either: common warts, flat warts, genital warts, or deep palmoplantar warts.
Warts are transmitted by direct or indirect contact, and disruption of the epithelial barrier (e.g. a cut in the skin) is a predisposing factor. A subset of HPV types has been associated with the development of malignancies: HPV 6, 11, 16, 18, 31, and 35 (unfortunately physicians do not in clinical practice test for specific strains at this time); malignant transformation is most common in those with genital warts or those who are immunocompromised.
The treatment of warts poses a therapeutic challenge for physicians as no general consensus on therapy to achieve complete remission in all patients has been reached. As a result, many different approaches to wart therapy exist with varying mechanisms of action and efficacy.
A ‘watch-and-wait approach’ is the first option to consider, since 65% of warts are believed to regress spontaneously within two years. However, non-treatment in patients with extensive, spreading, or symptomatic warts is not advised. The first line of therapy is the topical agents, particularly salicylic acid, which is effective for non-genital warts. Many salicylic acid preparations are available over the counter at concentrations up to 40%, can be applied at home, and have cure rates from 70-80%. Dermatologists may prescribe even stronger compounded acid mixtures containing trichloroacetic acid, salicylic acid and lactic acid. Podophyllotoxin can also be applied in the home setting. For flat warts, vitamin A acid/retinoids can also be considered as treatment.
There are several topical agents that are applied only in the physician’s office, and they include catharidin and powerful sensitizing agents such as diphencyprone in a treatment referred to as immunotherapy. Liquid nitrogen cryotherapy freeze-burns warts at almost -196 degrees Celsius and it can be used to treat warts in any location. 5-fluorouracil (5-FU) is a chemotherapeutic agent that has efficacy for warts. Imiquimod has also been used for warts with some success, although it is more useful for mucosal warts where absorption is much greater. For persistent and refractory warts, Bleomycin injections or Bleomycin tattooing can be effective treatment options (offered at our Toronto clinic).
The treatment of warts continues to pose a therapeutic challenge. Many different approaches to wart therapy exist with varying mechanisms of action and efficacy. The treatment options are quite variable and no single treatment or group of treatments is standard. Patients are often dissatisfied with recurrence, as a therapeutic regimen to achieve complete remission in all patients has not yet been developed.
Contact our medical clinic right away if you have warts or any lesions or rashes you’re uncertain about for a prompt diagnosis and discussion of the best treatment plan.