Flat warts are a common type of noncancerous skin growth, appearing as small, smooth bumps. Notably flatter and often smaller than other warts, they are also called “verruca plana.” They typically develop in groups and are frequently observed in children and young adults.
Appearance and Common Locations
Flat warts are small, smooth, and slightly raised bumps on the skin. They are notably flatter than other wart types, typically measuring 1 to 5 millimeters in width, roughly the size of a pinhead. They can be round or oval.
Their color varies, often blending with surrounding skin. They may appear flesh-colored, light pink, yellowish-brown, or light brown. On darker skin tones, they might be whitish, pink, purple, or brown. Unlike common warts, their surface is smooth, not rough or cauliflower-like.
Flat warts often appear in clusters, sometimes with dozens to over a hundred lesions. They are most often found on the face, particularly in children, and on the backs of the hands. Other common locations include the neck, arms, wrists, and legs, especially in areas prone to minor skin trauma from activities like shaving. They can also manifest in a linear pattern, following a scratch or cut.
Understanding the Cause and Transmission
Flat warts are caused by specific, non-cancerous strains of the human papillomavirus (HPV), primarily types 3, 10, 28, and 49. This common viral infection leads to an overgrowth of skin cells in the outermost layer, the epidermis, resulting in wart formation.
Transmission occurs primarily through direct skin-to-skin contact with an infected individual. The virus enters through tiny, often invisible, breaks in the skin. This is why flat warts often appear in areas prone to minor trauma, such such as from shaving on the beard area in males or legs in females.
Autoinoculation, transferring the virus from an existing wart to another body part (e.g., by scratching or shaving), can lead to new warts forming in a linear pattern. A weakened immune system, frequent skin trauma, poor hygiene, and moist environments can increase susceptibility and contribute to their spread.
Available Treatment Options
While flat warts may resolve naturally, treatment can accelerate their disappearance, reduce spread, and address cosmetic concerns. Treatment choice depends on the wart’s location, size, number, and individual preference.
Over-the-counter (OTC) options are often the first approach. Salicylic acid, available in liquids, gels, and pads, works by gradually peeling away wart layers. The wart is often soaked in warm water and gently filed before application. This method should be used cautiously on sensitive areas like the face, as irritation or scarring can occur.
Professional medical treatments offer stronger, more targeted approaches. Cryotherapy involves freezing warts with liquid nitrogen, causing a blister that eventually lifts the wart; multiple sessions may be required. Topical prescription creams, such as tretinoin (a retinoid) or imiquimod, are also used. Tretinoin disrupts wart cell growth, while imiquimod stimulates the body’s immune response to fight the virus, with daily application for several weeks or months.
Laser therapy uses a focused light beam to destroy wart tissue by targeting blood vessels. It can be effective for stubborn or numerous warts, especially in cosmetically sensitive areas to minimize scarring. Other professional treatments include acids like trichloroacetic acid or medications like 5-fluorouracil. Discuss all options with a healthcare provider to determine the most suitable treatment plan, as warts can recur even after successful removal.
When to Seek Professional Advice
While flat warts are often harmless and may resolve naturally, professional medical advice is recommended in specific situations. If uncertain about a skin growth, a doctor can provide an accurate diagnosis. This is important because some skin conditions resemble warts but require different management.
Consult a healthcare provider if warts become painful, itchy, bleed, or show signs of infection like redness or swelling. Rapid spreading or an increasing number of warts indicates active viral multiplication and warrants medical attention. When warts appear in sensitive areas like the face or genitals, professional treatment is often preferred to minimize scarring or complications.
Individuals with weakened immune systems (e.g., due to HIV/AIDS or certain medications) should seek prompt medical advice. Their bodies may struggle to clear the virus, leading to persistent or widespread warts. If over-the-counter treatments fail after several weeks, or if warts are bothersome, a doctor can offer stronger prescription options or in-office procedures.