How to Cope With a Ring Wart

A healthy 21-year-old man presented with a rapidly growing, filiform, ringshapedwart on his great toe (Figure). He said that initially he had a smallwart--about the size of the area in the center of the current "ring"--and thatit had been frozen 3 to 4 weeks earlier. Following the cryotherapy,a blister formed; this ruptured 2 times, after whichthe area began to heal. Then, the current wart arose atthe site.How often do warts like this develop followingcryotherapy? What treatment would you recommend?-- Swarna L. Yadlapalli, MD
   Moorhead, MinnThe treatment of verruca plantaris is very difficultbecause of the thick keratin and the presenceof human papillomavirus not only in thewarty tissue but also in the area surroundingthe wart (up to 2 cm away). A destructive modality,such as liquid nitrogen, kills the epidermal cellsthat constitute the clinical wart; however, it may alsotrigger replication of the latent adjacent virus throughthe growth factor that is produced as part of the woundhealing response. The replication of adjacent virusresults in the ring warts that are often seen on the feetand hands of patients whose warts have been treatedwith destructive modalities.At this point, I would recommend ablative carbondioxide or erbium yttrium-argon-garnet laser ablation ofthe wart with a 5-mm rim of normal epidermis. Keep inmind that more than one treatment may be required. Aless invasive alternative is 595-nm pulsed dye laser photocoagulationof the wart after careful paring. The benefitof this laser is that it does not create an open wound.However, several treatments, spaced 2 to 3 weeks apart, may be needed toclear a wart, and the treatment is quite painful.Immunomodulatory agents, such as imiquimod, squaric acid, and dinitrochlorobenzene,are generally not effective on glabrous skin because oflack of absorption. Intralesional bleomycin injections can be effective but arealso painful.Most warts will regress spontaneously given enough time. Thus, thebest treatment--if the wart is not too painful--might be benign neglector treatment with topical over-the-counter medications that contain salicylicacid.-- George J. Hruza, MD
   Clinical Associate Professor of Dermatology and Otolaryngology
   Head and Neck Surgery
   St Louis University School of Medicine
   St Louis