The definition of warts is variable, largely reflecting their manifold appearance, biologic potential, and public health concerns. One vernacular dictionary defines warts as:
Small, benign growths caused by a vital infection of the skin or mucous membrane. The virus infects the surface layer. The viruses that cause warts are members of the human papilloma virus (HPV) family. Warts are not cancerous but some strains of HPV, usually not associated with warts, have been linked with cancer formation. Warts are contagious from person to person and from one area of the body to another on the same person.1
The World Health Organization defines warts by their structural components as:
Human papillomavirus (HPV) is a small, non-enveloped deoxyribonucleic acid (DNA) virus that infects skin or mucosal cells. The circular, double-stranded viral genome is approximately 8-kb in length. The genome encodes for 6 early proteins responsible for virus replication and 2 late proteins, L1 and L2, which are the viral structural proteins.2
In pediatric and adolescent dermatology, warts often are defined by their location and morphology; for example, facial warts typically are flat, minimally hyperkeratotic, or filiform, wherein the base is narrow and the lesion is tall, growing at a 90° angle to the surface of the skin. On the arms and legs, warts usually present as round to oval papules with overlying thick hyperkeratosis and/or callosity.3,4 Common warts usually are flesh colored or lighter, and heavily pigmented lesions should be evaluated dermoscopically for a pigment network and biopsied when pigment is present.5
In this article, a successful paradigm for management of pediatric warts is provided with enhanced outcomes based on further insight into the disease course and patient selection.
Epidemiology of Pediatric Warts
There are more than 200 types of human papillomaviruses (HPV), with more than 100 oncogenic types. There is quite a bit of homology by species and genus that contributes to cross-immunity and similar behavior between certain types of HPV. The lifetime incidence of warts is very high. Approximately 30% of children develop a wart.6 A review of the 2007 National Health Interview Survey of 9417 children demonstrated a steady increase in prevalence of warts from 1 to 2 years of age to 7 to 8 years of age, with a peak at 9 to 10 years of age and a plateau at 11 to 17 years of age. Warts were most common in non-Hispanic white children and less common in black children.7 In an in-person survey of 12,370 individuals aged 18 to 74 years from 5 European countries, warts were the most common physician-diagnosed (27.3%) and self-reported (41.0%) dermatologic condition. Warts are more common in Northern countries (eg, Netherlands, Germany).8 Children with atopic dermatitis have a higher risk of developing warts and extracutaneous infections. In one study, children with warts and atopic dermatitis had a higher number of infections and food allergies and higher incidence of asthma and hay fever than either condition alone.9