This 14-year-old girl had first noticed the well-circumscribed, roughened, irregular growth on her right middle finger 6 months earlier. The lesion had progressively enlarged. The girl's mother had a similar, but smaller, lesion on the left elbow. Alexander K. C. Leung, MD, and Justine H. S. Fong, MD, of Calgary, Alberta, diagnosed verruca vulgaris. This proliferative, hyperkeratotic, exophytic lesion is most commonly caused by human papillomavirus types 2 and 4. The most frequently affected areas are the fingers, dorsa of hands, elbows, and knees. When the lesion surface is pared away, characteristic punctate black dots--representative of thrombosed capillaries and capillary bleeding--become visible.
The differential diagnosis includes molluscum contagiosum, seborrheic keratosis, and actinic keratosis. The diagnosis is usually clinical. Papillomatosis, hyperkeratosis, and parakeratosis are characteristic histologic features.
Treatment consists of the application of salicylic or trichloroacetic acid preparations or cryotherapy using liquid nitrogen. For optimal results, gently shave the hyperkeratotic surface with a scalpel until dark dots are apparent. Occlusive duct tape is also effective for this purpose.1,2 Resistant warts may respond to 5% 5-fluorouracil ointment, electrosurgery, or laser therapy.
This patient was successfully treated with liquid nitrogen and repeated shaving of the hyperkeratotic debris. The lesion did not recur.