Symptoms and causes

Symptoms

Plantar wart signs and symptoms include:

  • A small, fleshy, rough, grainy growth (lesion) on the bottom of your foot, usually the base of the toes and forefoot or the heel
  • Hard, thickened skin (callus) over a well-defined "spot" on the skin, where a wart has grown inward
  • Black pinpoints, which are commonly called wart seeds but are actually small, clotted blood vessels
  • A lesion that interrupts the normal lines and ridges in the skin of your foot
  • Pain or tenderness when walking or standing

When to see a doctor

See your doctor for the lesion on your foot if:

  • The lesion is bleeding, painful or changes in appearance or color
  • You've tried treating the wart, but it persists, multiplies or recurs
  • Your discomfort interferes with activities
  • You also have diabetes or poor sensation in your feet
  • You also have a weakened immune system because of immune-suppressing drugs, HIV/AIDS or other immune system disorders
  • You aren't sure whether the lesion is a wart

Causes

Plantar warts are caused by an infection with HPV in the outer layer of skin on the soles of your feet. They develop when the virus enters your body through tiny cuts, breaks or other weak spots on the bottoms of your feet.

HPV is very common, and more than 100 kinds of the virus exist. But only a few of them cause warts on the feet. Other types of HPV are more likely to cause warts on other areas of your skin or on mucous membranes.

Transmission of the virus

Each person's immune system responds differently to HPV. Not everyone who comes in contact with it develops warts. Even people in the same family react to the virus differently.

The HPV strains that cause plantar warts aren't highly contagious. So the virus isn't easily transmitted by direct contact from one person to another. But it thrives in warm, moist environments. Consequently, you may contract the virus by walking barefoot around swimming pools or locker rooms. If the virus spreads from the first site of infection, more warts may appear.

Risk factors

Anyone can develop plantar warts, but this type of wart is more likely to affect:

  • Children and teenagers
  • People with weakened immune systems
  • People who have had plantar warts before
  • People who walk barefoot where exposure to a wart-causing virus is common, such as locker rooms

Complications

When plantar warts cause pain, you may alter your normal posture or gait — perhaps without realizing it. Eventually, this change in how you stand, walk or run can cause muscle or joint discomfort.

Aug. 15, 2017
References
  1. Goldstein BG, et al. Cutaneous warts. http://www.uptodate.com/home. Accessed March 2, 2017.
  2. Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. March 14, 2017.
  3. Some wart removers are flammable. U.S. Food and Drug Administration. http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm381429.htm?source=govdelivery&utm_medium=email&utm_source=govdelivery. Accessed March 2, 2017.
  4. Landis MN, et al. Recalcitrant plantar warts treated with recombinant quadrivalent human papillomavirus vaccine. Journal of the American Academy of Dermatology. 2012;67:e73.
  5. Habif TP. Plantar warts. In: Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Edinburgh, U.K.; New York, N.Y.: Elsevier; 2016. https://www.clinicalkey.com. Accessed March 2, 2017.
  6. Kwok CS, et al. Topical treatments for cutaneous warts. Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001781.pub3/abstract. Accessed March 2, 2017.
  7. Warts. American Academy of Dermatology. http://www.aad.org/dermatology-a-to-z/diseases-and-treatments/u---w/warts. Accessed March 2, 2017.