Warts are non-cancerous skin growths caused by a viral infection in the top layers of skin. The virus that causes warts is called the human papilloma virus, or HPV:  Warts are usually skin colored and feel rough to the touch, but they can be dark, flat, and smooth.  The appearance of a wart depends upon where it is growing.

There are several different kinds of warts including:

Common Warts (verruca vulgaris) usually grow on the fingers, around the nails, and on the backs of the hands.  They are more common in skin that has been broken, such as areas where fingernails have been bitten or hangnails have been picked.  These are often called “seed” warts because the blood vessels to the warts produce black dots that look like seeds.

Plantar Warts (verruca plantaris) are common warts located on the soles of feet.  Warts on the palms (verruca palmaris) would be called palmar warts.  When many small plantar warts grow in clusters, they are known as mosaic warts because they fit together like mosaic tiles, making them more stubborn to treat.  Most plantar warts do not stick up above the surface like common warts because the pressure of walking flattens them and pushes them back into the skin.  Black dots may also be seen in these warts.  Plantar warts have a bad reputation because they can be painful and feel like a stone in the shoe.

Flat Warts (verruca-plana) are smaller and smoother than other warts.  They tend to grow in large numbers – 20 to 100 at any one time.  They can occur anywhere, but are most common on the face, in the beard area in men, and on the legs in women.  Irritation or microscopic cuts in the skin from shaving probably contribute to them.

Genital Warts (condylomata acuminata) are usually sexually transmitted and can be spread from close physical contact and repeated exposures.  They are also seen in infants who have been delivered vaginally to mothers with HPV in their genital tract.  Genital warts are flesh-colored, and may be rough or smooth.  They can be large or small and found as a single growth or in groups.  Genital warts appear on the genitals, inside the vagina, on the cervix, or around the anus.

Wart viruses occur more easily if the skin has been damaged in some way, which explains the high frequency of warts in children who bite their nails or pick at hangnails.  Just as some people catch colds very easily, some people are more likely to catch the wart virus than others.

How are warts treated?

A variety of treatments are available including Salicylic acid, Cantharidin, Cryotherapy, Injections, Laser Treatment, and Surgical Removal along with several possible Immunologic directed therapies. The treatment option is depending upon the age of the patient, the location of the wart, and the type of wart.