CUSTOM DERMATOLOGY SEARCH:
External Genital Warts
M. Bourcier, MD, FRCPC1; D. R. Thomas, MD, FRCPC2
Human papillomavirus (HPV) is a very common sexually-transmitted disease that is associated with a number of benign, premalignant, and frankly malignant lesions of the anogenital tract. In Canada, its prevalence varies depending on a number of risk factors, but appears to be highest in people between 15-25 years of age. [Varela A, et al. Skin Therapy Lett – US FP Ed 1(2): 1-3 (2007 winter).] ThSkin The introduction of a relatively new immunomodulator, and the approval of a vaccine significantly improves treatment options in managing this condition.
Condyloma Acuminatum (anogenital warts) is a common form of HPV infection. The majority of these are due to infection with HPV 6 or 11, and are clinically benign. Genital warts are usually asymptomatic, but can cause pruritus, bleeding, or mild burning. The warts present as:
Lesion color can range from flesh-colored to pink to reddish brown, and often they are multifocal. Lesion distribution generally corresponds with the areas of highest friction during sexual activity.
The virus is inoculated directly into the epidermal layers of the skin through epithelial defects, especially with maceration. Genital infections are primarily contracted through sexual contact. These infections can then be transmitted to newborns via passage through the infected birth canal. [Kaye JN, et al. J Gen Virol 77(Pt 6):1139-43 (1996 Jun).]
In the majority of patients, treatment can induce wart-free periods; if left untreated, warts may resolve on their own, remain unchanged, or increase in size or number. Treatment can reduce, but does not eliminate, HPV infection. The choice of treatment should be guided by the preference of the patient, the available resources, and the health provider’s experience. No single treatment is ideal for all patients or all warts. The majority of patients require a course of therapy rather than a single treatment, and improvement will generally be seen within 3 months. [CDC. Genital Warts Treatment Guidelines 2006. URL: http://www.cdc.gov/std/treatment/2006/genital-warts.htm.] Before beginning any treatment, it is essential to screen patients for other sexually-transmitted diseases.
Most treatment modalities treat the symptom of the disease (warts) versus the disease itself. However, imiquimod, goes further by inciting an immunologic response, thereby providing a field effect in clinical and subclinical HPV.
There are three treatment modalities:
Figure 1: Algorithm for treatment of suspect lesions. [Adapted from Varela A, et al. Skin Therapy Lett – US FP Ed 1(2):1-3 (2007 Winter).] TCA= trichloroacetic acid
A quadrivalent HPV recombinant vaccine is now available in Canada, and is indicated in girls and women aged 9-26 years for the prevention of diseases caused by HPV types 6, 11, 16, and 18, which include genital warts, cervical cancer and other neoplasias of the cervix, vagina and vulva. It should be administered IM as three separate 0.5ml doses. Studies with this vaccine are now ongoing in males. Another bivalent HPV vaccine (for HPV types 16 and 18) is currently under review with Health Canada. There is no evidence for effectiveness in treating those who already have genital warts.
Most HPV infections are asymptomatic and can spontaneously clear on their own. However if treatment is required, there are a number of antiproliferative, destructive, immunomodulatory modalities available. Combination therapies have been shown to be advantageous. In general, the response time can be expected within 3 months of therapy. Patients should be evaluated throughout the course of therapy for treatment response and side-effects, and treatment should be changed if substantial improvement is not seen within that time frame. Cryotherapy combined with imiquimod appears to be very commonly used. A quadrivalent HPV recombinant vaccine is now available for girls and women 9-26 years of age, and a bivalent vaccine is under review with Health Canada. While not of benefit to those already infected, future generations may be spared considerable burden from external genital warts due to the development, approval, and release of HPV polyvalent vaccines. Not only does the vaccination largely prevent incident external genital warts, but it also protects against genital tract HPV-associated neoplasia.
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Last modified: Thursday, 21-Jun-2012 16:58:58 MDT