Human Papillomavirus Infection




Introduction

HPV infection is a condition contracted from one of a group of more than 100 related human papillomaviruses (HPVs).

Each type of HPV has the potential to cause an abnormal growth on a particular part of your body — genital warts and other lesions on or near your genitals or anus, common warts on your hands, plantar warts on your feet, and warts and other lesions in your mouth and upper respiratory system.

HPV infections are common. It's estimated that close to 25 million people in the United States have HPV infections that can cause genital warts and related lesions.

Some types of HPV infection can cause cancer of the cervix, the narrow outlet of the uterus. Other HPV infections may cause other cancers of the genitals, anus, mouth or throat. However, not all infections with these dangerous types lead to cancer.

Treatments for HPV infections primarily focus on the removal of warts or lesions that cause embarrassment or discomfort and the removal of lesions that pose a risk of developing into cancerous (malignant) growths. A vaccine may prevent the most common types of HPV infection associated with either genital warts or cervical cancer.

Signs and symptoms

Most HPV infections go undetected because they don't cause warts or other lesions. Even if you don't exhibit signs and symptoms of the infection, they may emerge later and you may transmit the virus to someone else.

The signs and symptoms that do appear vary according to the type of HPV infection you may have:
  • Genital warts. Genital warts are nonmalignant and appear as a flat lesion, a tiny cauliflower-like bump or a tiny stem-like protrusion. HPV infections of types 6 and 11 cause most genital warts. These HPV types are generally not associated with cancer.
    In women these warts appear most commonly on the vulva but may also occur near the anus, on the cervix or in the vagina. In men these may appear on the penis and scrotum or around the anus. Genital warts rarely cause discomfort or pain.
  • Pre-malignant genital lesions. Certain HPV infections can cause cellular changes that indicate the presence of precancerous lesions. These abnormalities are most often detected by a Pap test, a simple procedure to collect cells from the cervix or vagina for laboratory examination.
    Abnormalities that are determined to be "low grade" usually resolve — the cells return to normal — without treatment. HPV infections of types 6 and 11 are common causes of these low-grade abnormalities.
    High-grade abnormalities are less likely to resolve, and some will advance to cancer, most commonly cervical cancer. HPV infections of types 16 and 18 are the most common causes of high-grade abnormalities.
  • Oral and upper respiratory lesions. Some HPV infections may cause warts and other lesions to form on your tongue, tonsils, soft palate, and larynx and in your nose. These lesions may be the result of low-risk HPV types, such as 6 and 11, and high-risk types, such as 16 and 18.
  • Cervical cancer and other tumors. Most genital HPV infections of high-risk types don't develop into cancer; however, persistent infections — generally lasting more than two years — create a greater risk of cancer.
    Virtually all cases of cervical cancer are caused by HPV infections. An estimated 10,000 women in the United States are diagnosed with cervical cancer annually, and about 4,000 die of the disease each year. Worldwide, cervical cancer is far more common because many women lack access to Pap test screening. Types 16 and 18 account for about 70 percent of all cases of cervical cancer.
    HPV infections of type 16 and 18, as well as other high-risk types, may also contribute to cancers of the genitals, anus, mouth and upper respiratory tract.
  • Common warts. Common warts are nonmalignant skin growths that usually appear on your hands, fingers or around fingernails. These warts appear as rough, raised bumps. They're generally nuisances because of their appearance, but they may also be painful or susceptible to injury or bleeding.
    Most children and adolescents have been exposed to HPVs that cause these warts, but only some actually get warts. Most people don't get common warts after age 20.
  • Plantar warts. Plantar warts are hard, grainy, nonmalignant growths that usually appear on the heel or ball of your feet, areas that feel the most pressure. These warts may cause discomfort or pain. Although plantar warts are common in adulthood, the virus was most often encountered first as a child or adolescent.
  • Flat warts. Flat warts are flat-topped, slightly raised, nonmalignant lesions darker than your regular skin color. They usually appear on your face, neck, hands, wrists, elbows or knees. HPV infections that cause flat warts usually affect children, adolescents and young adults.
Causes

HPV infection occurs when the virus enters your body through a cut, abrasion or imperceptible tear in the outer layer of your skin. The virus is transferred primarily by skin-to-skin contact.

HPV infections associated with genital warts and related lesions are contracted through sexual intercourse, anal sex and other skin-to-skin contact in the genital regions. Some HPV infections that result in oral or upper respiratory lesions are contracted through oral sex.

Rarely a mother with an HPV infection may transmit the virus to her infant during delivery. This exposure may cause HPV infection in the baby's genitals or upper respiratory system.



Treatment

There's no cure for HPV infection. In most cases, your immune system rids your body of the virus, and warts often go away without treatment.

A number of treatments — applied at home or performed by a doctor — are available to remove warts. These treatments appear to reduce the concentration of HPV, but they don't eliminate the virus. For example, even though you may have genital warts removed, you can still transmit HPV to a sexual partner.

Genital warts
Treatments for genital warts include:
  • Imiquimod (Aldara), a prescription medication applied as a cream that may enhance your immune system's ability to fight HPV
  • Podofilox (Condylox), also applied as a cream, which may destroy the genital wart tissue
  • Trichloroacetic acid, a chemical treatment that burns off genital warts
  • Freezing with liquid nitrogen (cryotherapy)
  • Electrocautery, which uses an electrical current to burn off warts
  • Surgical removal
  • Laser surgery
Treatments for high-grade pre-malignant lesions
Your doctor will most likely not treat low-grade pre-malignant lesions, because they're likely to go away on their own and not develop into cancer. However, you'll need to return for follow-up Pap tests to make sure the problem has resolved.

Your doctor will most likely recommend removal of high-grade pre-malignant lesions, because they may develop into cancerous tumors. Treatments may include:
  • Cyrotherapy
  • Electrocautery
  • Surgical removal
  • Laser surgery
Treatments for other warts
Treatments for common plantar and flat warts include:
  • Salicylic acid, which removes layers of a wart a little bit at a time
  • Imiquimod (Aldara)
  • Cyrotherapy
  • Surgical removal
  • Laser surgery
Prevention

Genital warts and related lesions You can reduce your risk of developing genital warts and other HPV-related genital lesions by:
  • Being in a mutually monogamous sexual relationship
  • Reducing your number of sex partners
  • Using a latex condom, which may prevent some but not all HPV transmission
A vaccine called Gardasil is available for women to prevent HPV infections of types 6, 11, 16 and 18. Ideally, a woman should receive this vaccine before becoming sexually active. The vaccine protects women only from contracting HPV infections of types they haven't already encountered.

According to the Centers for Disease Control and Prevention, the HPV vaccine should be a part of the regular immunization regime for 11- to 12-year-old girls. This vaccine is a powerful new tool in the fight against cervical cancer, and most pediatricians will strongly encourage HPV immunization for girls in the recommended age group.

Most adolescent girls or women who are sexually active will derive some benefit from HPV vaccination. If you've already acquired an HPV infection, it's unlikely that you've encountered all types included in the vaccine. For most people who are at risk of HPV infection, the potential benefits of getting the vaccine outweigh the known risks. Side effects in clinical trials were primarily mild pain at the injection site. Talk to your doctor about getting an HPV vaccination if you believe you're at risk of infection.

HPV vaccination is currently not recommended for boys or men, but the benefit of this immunization strategy is under investigation. Vaccination of males would likely have significant benefit for their future sexual partners.

Common warts
It's difficult to prevent HPV infections that cause common warts. If you have a common wart, you can prevent the spread of the infection and formation of new warts by not picking at a wart and not biting your nails.

Plantar warts
You may reduce the risk of contracting HPV infections that cause plantar warts by keeping your feet clean and dry, wearing clean socks, and wearing shoes or sandals in public pools and locker rooms.

Informations obtained from National Institute of Health.
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