When the human papillomavirus, or HPV, infects the skin on your thumb, it causes a common wart to develop. Warts grow in the surface layers of the skin, so they are seldom very deep; however, they can be large, persistent and difficult to remove. If you suspect that your wart is much deeper than the surface of your skin, see a doctor to make sure you don't have a more serious skin condition.
Causes
HPV is contagious, so a common way to develop warts is to touch someone else who has them. The virus survives outside the human body long enough for you to catch it indirectly, too; if you touch an object that has just come into contact with a wart, you can pick up HPV from the object. Warts often develop on the hands, because hands are likely to be exposed to the virus. HPV enters the body through breaks in the skin, so warts often grow in hangnails or cuts on the thumb.
Severity
A relatively deep or large wart on the thumb actually may be a cluster of smaller warts. If you bite your nails or pick at hangnails, you can cause small tears in the skin and spread the virus around the surface of your thumb. Warts may look particularly deep or serious if they have seeds, which are small, black dots within the growth. These dots are tiny blood clots inside vessels in the infected area of skin and don't mean that the wart is unusually deep. Wart seeds do not require special medical attention.
Home Treatment
Warts heal on their own, given enough time. However, you may want to treat a thumb wart to avoid spreading the infection. Over-the-counter wart patches cover the infected area with salicylic acid, which kills the warty skin and lifts it off the healthy skin. Apply a wart patch after soaking your thumb in warm water for 10 to 20 minutes and use a pumice stone to buff off the dead skin when you remove the patch. Apply salicylic acid to the wart carefully to avoid damaging healthy skin. You may have to repeat the treatment daily for several weeks.
Medical Treatment
If you have large numbers of warts or your infection does not fade on its own, talk to your doctor about treatment options. He may recommend cryotherapy or cantharidin treatments that cause the skin beneath and around the wart to blister. This separates the wart from the healthy skin and allows the doctor to scrape it off. For persistent, large warts, he may suggest a surgical procedure in which he removes the wart with a needle. Talk to your doctor about which treatment is the best option for you, based on the location and size of your wart.
