What Works for One Wart May Work for Another

My patient is a 7-year-old girl with multiple plantar warts on both feet. Warts hadfirst appeared on her right foot about 8 months earlier. The mother had treated theselesions daily for about 3 months with an over-the-counter salicylic acid preparation.However, the lesions did not regress, and recently more appeared on the other foot.Imiquimod 5% cream is indicated for external genital warts. Can it also beused to treat plantar warts in children?--Karen van Nieuwenhuizen, MSc, PA-C
   Prescott, ArizImiquimod 5% cream is approved by the FDA for thetreatment of external genital warts in both malesand females aged 12 years or older. This agent neitherdestroys tissue nor interferes with viral metabolism.Rather, it is an immunomodulator that enhances selectedaspects of the patient's own innate and acquired immuneresponse to the human papillomavirus (HPV).Since both genital and extragenital warts are causedby HPV, it seems logical that imiquimod would also beof benefit in the management of verruca vulgaris and verrucaplantaris. The problem with imiquimod is that itdoes not penetrate well through thick skin or thick lesions.Therefore, some ancillary agent or technique must beused to ensure adequate penetration. My personal recommendationis to:1. Pare the wart.2. Administer light liquid nitrogen cryotherapy.3. Instruct the patient to do the following:

• Apply imiquimod cream nightly, occluded by a breathabletransparent dressing, plastic wrap, or duct tape.
• Remove occlusive material and wash area in themorning.
• Apply a topical retinoid gel (eg, tretinoin 0.025% ortazarotene 0.1%) after washing off imiquimod.
• Continue occluded imiquimod each night and unoccludedretinoid gel each morning for 4 weeks.

4.

Have the patient return 1 month later. If the lesion hasnot resolved, repeat paring and freezing and continuethe imiquimod-retinoid regimen for an additional 4 weeks.I find that many warts will respond to 2 such cyclesof treatment, including those that have previously resistedconventional monotherapy.As noted, the drug's FDA-approved use extendsonly to patients age 12 or older. However, it has beenwidely and safely used in younger patients to treat bothwarts and molluscum contagiosum.

--Ted Rosen, MD
   Professor of Dermatology
   Baylor College of Medicine
   Houston

Editor's note: We recently received a letter from another reader who describes hertreatment of common warts with imiquimod cream.

I work in a children's health clinic. I find that many children have commonwarts on their fingers that do not respond to the conventional noninvasiveduct tape therapy. We do not have liquid nitrogen at our clinic to freeze offthe warts--which in any event might be painful to young children. I recentlyreferred a patient to a dermatologist for management of the problem. Sheencouraged me to try imiquimod cream, applied to the area twice a day andcovered with duct tape, to help resolve the warts. I found this suggestion veryhelpful.

--Tajuana Crosby, PA-C
   Clayton, NC