Warts are infections in the skin caused by the human papillomavirus (HPV). There are more than 100 types of HPV that are responsible for the many different types of warts, which include common warts, plantar warts, flat warts and genital warts.
Warts are common, particularly in childhood. Some estimates suggest that up to one in five children have warts, with children aged 12 to 16 years most commonly affected. Without medical treatment, many wart infections go away by themselves.
Symptoms of warts
The characteristics of a wart depend on the type, but can include:
- A small, raised bump may appear on the skin.
- The average size can range from one to 10 millimetres.
- The wart may have a rough or smooth surface.
- Warts can occur singly or in clusters.
- In some cases, the wart may itch.
- Face, feet, knees and hands are most commonly affected.
Types of warts
Some of the types of warts caused by HPV include:
- Common warts (verruca vulgaris) – these look like hard, raised lumps with rough surfaces. Any body part can be affected, but the knees and hands are the most common sites.
- Flat warts (verruca plana) – these look like smooth, flattened lumps. Any body part can be affected, but the face, lower legs and hands are the most common sites.
- Filiform warts – these look like thin, long threads. The face is usually affected, particularly near the eyelids and lips.
- Mosaic warts – these appear as a group of tightly clustered warts. The hands and soles of the feet are most commonly affected.
- Plantar warts – these look like small, hard bumps, and can have tiny black dots on them. The soles of the feet are most commonly affected.
- Genital warts – these look like grey or off-white lumps with a grainy ‘cauliflower’ appearance. Since genital warts are sexually transmitted, the penis, vulva and anus are most commonly affected. Some common types of genital warts predispose women to cancer of the cervix
Risk factors for warts
Anyone can develop warts, but factors that increase the risk include:
- injuries to the skin
- skin infections that break the skin surface
- frequently getting the hands wet
- hands or feet that sweat heavily (hyperhidrosis)
- swimming in public swimming pools
- nail biting
- direct contact with other people’s warts
- scratching or shaving your own warts, which can spread the infection to other areas of your body.
Diagnosis of warts
Most warts are easily recognised. For unusual warts, see your doctor for a proper diagnosis.
Treatment for warts
There are many different treatments for warts. Make sure you talk to your doctor about the risks and benefits of your treatment as some cause scarring. Warts can be stubborn, so you may need to use more than one type of treatment.
Some of the wart treatment options include:
- Do nothing – about 65 per cent of warts clear up by themselves within two years, without any medical intervention. However, new warts occur three times as frequently in infected children as in uninfected ones. This ‘wait and see’ approach isn’t recommended for people with multiple warts, or for those who have had their warts for more than two years.
- Topical (applied to the skin) chemicals – such as salicylic acid or lactic acid. Some topical agents can be harmful to healthy skin tissue, which means they are best applied by your doctor or dermatologist. Other topical agents can be applied yourself. It may take three months or more for the treatment to get rid of the warts.
- An immune system stimulator – such as imiquimod – can be used for genital warts. It stimulates the immune system to fight the viral infection. A similar way to invoke the immune system is with DPCP (diphenylcyclopropenone). A person is made hypersensitive to this chemical and then low concentrations are applied around the wart, encouraging immune cells to invade and destroy the wart. DPCP is only available in specialist clinics.
- Cryotherapy – the warts are frozen with liquid nitrogen. It may take up to four months of regular cryotherapy to get rid of the warts.
- Laser therapy – a laser is used to burn off the warts. Scarring may occur.
- Gardasil vaccination is now provided to teenage girls to protect them against HPV strains associated with genital warts and cervical cancer. It is not generally recommended to treat existing warts.
- If you suspect you have genital warts, you should see your doctor about treatment. A wait and see approach to genital warts is not recommended. For adult women infected with genital warts, a Cervical Screening Test should also be done to screen for cancer of the cervix.
Where to get help
- Your doctor
- National Cervical Screening Program Tel: 13 15 56
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