What are Plantar Warts?

Plantar warts can develop on any part of the foot. Sometimes dark specks are visible beneath the surface of the wart. When pressure from standing or walking pushes a plantar wart beneath the skin’s surface, a layer of thick, tough skin similar to a callus, develops over it. As the callus and wart get larger, walking can become painful, much like walking with a pebble in your shoe. Multiple warts and plantar warts can form in a large, flat cluster known as a “mosaic wart.”

Causes
The HPV type 1 causes most plantar warts. The virus gains access to the skin through direct contact. It is presumed that inoculation of the skin probably occurs in places likely to be contaminated by others with plantar warts, like communal showers. There are a variety of innate mechanisms that seem to be important in resisting infections. Once infected by HPV, spontaneous resolution seems to depend on the development of immune lymphocytes that destroy the virus-infected cells. It appears that the levels of neutralizing antibodies in the blood induced by vaccination with HPV proteins can protect against certain types of infections.

Signs and Symptoms
Foot pain that feels like a lump under the foot
Leg or back pain possibly caused by poor posture
Firm, warty (rough, bumpy, and spongy, some appear thick and scaly) lesions with tiny pinpoint dark spots inside (not always apparent): These dark spots are minute, thrombosed (containing blood clots) capillaries in the deeper layers of the skin.
Smooth surface with a gray-yellow or brown color
Located over areas of pressure or bony point such as the heel and ball of the foot
Usually flat because of pressure
Several warts may fuse to form mosaic warts

Treatments
Acid: One of the most common methods is to burn warts off with a mild acid applied topically to the wart. Many applications may be required over the course of several weeks to achieve this, but the technique is highly successful. Salicylic acid and dichloroacetic (or trichloroacetic) acid are useful.
Other acid methods may be used.

Salicylic acid in white soft paraffin: A mixture of 40%-60% salicylic acid in white soft paraffin is applied daily after showering and covered with waterproof tape. You pare the wart once a week with a sharp blade.
Efudex (5-fluorouracil), although not an acid, is another topical ointment that can destroy wart tissue in a manner similar tochemotherapy for skin cancer.

Laser treatment: New technology has enabled doctors to use lasers to destroy the wart. The procedure, performed in the physician’s office, is expensive and is likely to result in some scarring. Its efficacy in comparison to other destructive approaches is unproven.