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Flat wart in Adult
See also in: External and Internal Eye
Other Resources UpToDate PubMed

Flat wart in Adult

See also in: External and Internal Eye
Contributors: Gabriela Ulloa MD, Loren Krueger MD, Belinda Tan MD, PhD, Susan Burgin MD
Other Resources UpToDate PubMed


Flat warts (also known as verruca plana and plane warts) are 1-3 mm, round or oval, slightly raised, smooth papules induced by human papillomavirus (HPV) types 3, 10, 28, and 49. Flat warts are commonly painless and can be yellowish-brown, skin-colored, or pink. They may appear singularly, in clusters, or in a linear arrangement. Flat warts typically present on areas of the body that have contact with other people and objects, such as the face, arms, hands, and feet; however, they can appear anywhere on the body.

The warts arise from benign strains of HPV and are not known to cause cancer. They are contagious and spread easily over the body. Transmission is commonly via person-to-person contact or via fomites. Existing skin trauma (ie, cuts, scratches, burns, eczema) predisposes patients to contracting HPV. A person with flat warts may spread the warts to a different part of the body (autoinoculation) through trauma to the skin such as scratching or shaving.

Children, young adults, and immunocompromised patients are most susceptible. Widespread or extensive warts are often presenting signs of an immunocompromised state. Warts may be more numerous and more difficult to treat in immunocompromised patients. Excessive sun exposure can lead to exacerbation.

While warts are normally self-limited in children, they may be difficult to treat in adults. Longer periods of treatment are usually necessary for adults.


B07.8 – Other viral warts

240539000 – Flat wart

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Last Reviewed:04/02/2018
Last Updated:04/19/2018
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Patient Information for Flat wart in Adult
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Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). The virus causes thickening of the top skin layer. Flat warts tend to stay small in size but can be numerous in quantity. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).

Warts are usually acquired from person-to-person contact. The virus is not highly contagious but can cause an infection by entering through a small break in the skin. In the same way, warts can be spread to other places on your own body. The virus is rarely transferred by touching an object used by an infected person.

Who’s At Risk

Warts can affect people of any age, but they are most common in those between 12 and 16 years old. It is estimated that 20% of schoolchildren and about 10% of the general population have warts. Those with HIV or organ transplants or on chemotherapy have a higher incidence of warts because of their weakened immune system.

Signs & Symptoms

The most common locations for flat warts include:
  • Face, especially in children
  • Legs, especially in women
  • Beard area, especially in men
  • Backs of hands
  • Arms
Flat warts are very slightly raised, smooth, skin-colored bumps ranging in size from 1-5 mm. Flat warts are usually numerous in quantity and may appear in a line due to auto-inoculation from scratching or shaving.

Infection with flat warts can be described as:
  • Mild - one or a few painless warts
  • Moderate - 10-100 lesions, which are painless
  • Severe - more than 100 lesions, which cause enough pain to limit normal life activities

Self-Care Guidelines

Because warts can resolve on their own, it is not necessary to treat all warts. Additionally, treating warts may not always destroy them, nor will it necessarily keep other warts from appearing. Treatment can be painful and cause scars and might need to be repeated, so it should only be done in cases where the warts are highly bothersome or interfere with daily life.
  • Over-the-counter wart removers have a high percentage of salicylic acid and work by dissolving away the layer of skin infected with the virus. This needs to be used daily and can sometimes be irritating if it touches unaffected skin around it.
  • Duct tape applied daily to the affected area seems to work for unknown reasons. The tape should be very sticky and kept on for a few days.
  • Over-the-counter freezing medications are available but have not been found to be very effective.
  • Coupled with the above therapies, the wart should be soaked in warm water, and any loose skin should be removed every few days with a mild abrasive, like a pumice stone.
  • Family members should avoid sharing personal items such as towels.

When to Seek Medical Care

Make an appointment with a dermatologist or another physician if you have:
  • Painful or bleeding warts
  • Warts on the face
  • Rapidly spreading or multiplying warts
  • Warts that interfere with daily life and are not responsive to self-care


Once you have been diagnosed with flat warts, your physician may try one or more of the following treatments:
  • Freezing with liquid nitrogen (cryosurgery)
  • Burning with an electric needle (electrocautery)
  • Using a laser to disrupt the blood supply of the warts
  • Application of cantharidin, podophyllin, tretinoin, or salicylic acid
  • Injection with bleomycin, a chemotherapy drug, directly into the warts
  • Application of imiquimod, a cream that induces your immune system to destroy the wart


Bolognia, Jean L., ed. Dermatology, pp.1223, 1226-1227. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. pp.2121, 2123-2124, 2128-2129. New York: McGraw-Hill, 2003.
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Flat wart in Adult
See also in: External and Internal Eye
A medical illustration showing key findings of Flat wart : Tiny papules, Hyperpigmented papules
Clinical image of Flat wart - imageId=1881660. Click to open in gallery.  caption: 'Many discrete, pink and light brown, flat-topped, verrucous papules scattered over the dorsal hands. Note the linear arrays of warts indicative of autoinoculation.'
Many discrete, pink and light brown, flat-topped, verrucous papules scattered over the dorsal hands. Note the linear arrays of warts indicative of autoinoculation.
Copyright © 2023 VisualDx®. All rights reserved.