Warts, molluscum and things that go bump on the skin: a practical guide

Evidence-based medicine is a wonderful thing. It keeps much of the quackery and snake oil that plagues our field at bay. Sometimes, however, it creates a paradox in which clinicians become trapped, lamenting that because there is no evidence, nothing can be done. I find this notion particularly concerning, both in terms of the danger of stagnation in medicine, and, more importantly, as a philosophy in treating actual human beings. In the immortal words of the renown dermatologist Walter B Shelley: “Therapeutic nihilism may be the correct way to approach the facts, but not the patient.”1

Fortunately, none of these concerns applies to the treatment of warts and molluscum. People have used everything from duct tape to antacids to treat these common cutaneous maladies, and lack of evidence has not diminished the therapeutic enthusiasm in the least. As such, there are literally entire textbooks devoted to the subject.2

The present work does not attempt to be an exhaustive guide or review for all these therapies; rather I will focus on a few key practical points that hopefully will be helpful in navigating the thick foliage of this therapeutic jungle.

THE BUMPS

Warts are extremely common viral infections of the skin. The human papillomavirus (HPV) is responsible for warts and actually represents a large group of closely related viruses with over 100 types. HPVs can infect any site with stratified squamous epithelium, including mucosal surfaces. Interestingly, many of the HPV types roughly correspond to clinical phenotypes. HPV type 1, for example, is associated with plantar warts, while type 28 is associated with flat warts.3

Although warts themselves often appear as well-defined tumours, the HPV can be present at very distant sites of the body and for many years. Remarkably, one study showed that nearly 70% of a healthy control group …