HPV is a common group of over 200 viruses that infect the skin and mucous membranes. While some strains cause serious health conditions, most are responsible for benign skin growths known as warts, or verrucae. In children, HPV infection almost exclusively manifests as cutaneous warts, which are non-sexually acquired and generally resolve without complication. This widespread viral infection is highly prevalent in the pediatric population.
Primary Ways Children Contract HPV
Children primarily contract HPV through non-sexual, horizontal transmission, meaning the virus spreads through everyday contact with infected skin cells. Direct skin-to-skin contact is the most frequent route, such as holding hands or sharing close personal space with someone who has an active wart. The virus is more likely to enter the skin through small breaks, like scrapes, cuts, or areas of moist skin.
Indirect contact via contaminated objects, known as fomites, is another common pathway because HPV can survive on surfaces. This includes shared items like towels, socks, nail clippers, or shoes. The virus thrives in warm, moist environments, making communal areas such as public swimming pools and shared showers a source of infection.
A child may also spread the virus across their own body through autoinoculation, which occurs when they scratch or pick at an existing wart and then touch an uninfected area. Vertical transmission, where the virus is passed from a mother to her infant during birth, is a less common route. This mechanism is primarily associated with mucosal HPV types and rarely causes common skin warts.
Recognizing Common Pediatric Warts
Cutaneous warts are classified based on their appearance and location, though they are caused by specific, low-risk HPV types. The most common type is the Common Wart (verruca vulgaris), characterized by a rough, dome-shaped surface resembling a miniature cauliflower head. These warts are typically grayish-yellow or brown and frequently appear on the fingers, hands, knees, and elbows.
Plantar Warts (verruca plantaris) develop on the soles of the feet, usually where pressure is greatest. Due to constant pressure, these warts grow inward, which can cause pain described as stepping on a stone. They often appear flattened and may be covered by a thick layer of callus, sometimes showing tiny black pinpoints (clotted blood vessels).
Flat Warts (verruca plana) are distinctly different, presenting as small, smooth, and slightly raised lesions with flat tops. They are usually flesh-colored and are most common on the face and the backs of the hands, frequently appearing in large clusters.
Treatment Options for Childhood Warts
Watchful waiting is the preferred first strategy, as approximately two-thirds of cutaneous warts resolve spontaneously within two years when the child’s immune system clears the virus. Treatment is pursued if the wart is painful, spreading rapidly, or causing psychological distress. The most accessible first-line treatment is over-the-counter salicylic acid, available in liquid, gel, or patch form up to 40%.
Salicylic acid works through a keratolytic action, gradually dissolving the thick, infected layers of the skin. This home treatment requires daily application after soaking and gently filing the wart, a process that can take three to six months for clearance.
For warts resistant to home treatment, a healthcare provider may perform in-office cryotherapy, which involves freezing the wart with liquid nitrogen. Cryotherapy is a faster, more destructive method, but it can be painful and is reserved for older or more cooperative children.
Other prescription options exist for recalcitrant or sensitive-area warts, including topical medications like the retinoid Tretinoin or the antiviral agent 5-Fluorouracil. These compounds target the infected cells and are often used for flat warts or those located on the face.
Addressing Parental Concerns and Prevention
A common concern for parents is the source of the infection, and it is important to clarify that common skin warts are acquired through routine, non-sexual contact. The low-risk HPV strains that cause these benign growths are ubiquitous, and their presence is not indicative of sexual activity or abuse. Focusing on simple hygiene measures can significantly reduce the risk of transmission and autoinoculation.
Parents should encourage children to avoid walking barefoot in public, moist environments like pool decks, locker rooms, and communal showers, instead opting for flip-flops or sandals. Since the virus can spread through shared items, children should use their own towels, socks, and nail clippers. Covering existing warts with a bandage is also an effective way to prevent the virus from spreading to other parts of the body or to other people.
The HPV vaccine, Gardasil 9, is recommended for pre-teens beginning at ages 9 to 12 as a defense against high-risk strains responsible for cancers and the low-risk strains that cause genital warts. While the vaccine is not primarily designed to prevent common cutaneous warts, some evidence suggests it may offer a degree of cross-protection. The vaccine’s main benefit remains the protection against more serious HPV-related diseases.