Warts are small growths on the skin caused by a virus known as human papillomavirus (HPV). Warts are extremely common: it is estimated that about 25% of the population have a wart at any one time. Luckily, most warts are harmless. However, since they're caused by a virus, warts are very contagious.
Warts can grow anywhere on the skin. There are 6 clinically different types:
- Common warts have a rather bumpy surface and appear most often on the hands and fingers (of children, in particular).
- Flat or plane warts are small, smooth warts appearing in clusters on the back of the hands, face, or legs.
- Plantar warts are those appearing on the soles of the feet.
- Filiform warts form long, thin projections around the eyes, face, and neck.
- Periungual warts (common in people who bite their nails) occur under and around the fingernails.
- Genital (venereal) warts are those appearing on the genitalia.
Keep in mind that some warts can become cancerous, and some skin cancers can look like warts, so always get them checked by your doctor. Also remember, the sooner a wart is treated, the easier it will be to destroy - so don't procrastinate.
Warts can be caused by 70 different strains of HPV. These viruses exist naturally on human skin, so when a person's immune system is weak (from illness or medications) he or she is at a higher risk of contracting the virus.
Common, plantar, or plane warts can be acquired through something as simple as a cut. Walking barefoot in public areas is also a high-risk activity for contracting warts. Genital warts are more serious and also the most contagious. They are transmitted through direct sexual contact and may take from 1 to 24 months to appear.