Human papillomavirus (HPV) is one of the most common sexually-transmitted infections. It is part of the papillomaviridae family, and can be contracted at any point during an individual’s life, while they are sexually active. And in the vast majority of cases, it is harmless and asymptomatic.
HPV has two main characteristics: it only multiplies in the nuclei of epithelial and mucosal cells of stratified epithelia, and it is potentially highly carcinogenic.
But before we go any further, we should make a couple of clarifications in this regard:
- Firstly, you might be asking yourself what on earth stratified epithelia are. These are epithelia formed by several different layers (strata) of cells.
- And does the fact that it can be carcinogenic mean that HPV always causes cancer? The answer is no – not all types of HPV cause cancer. In fact, most infections involving this virus are completely asymptomatic.
Types of Human Papillomaviruses
More than one hundred types of human papillomavirus have been discovered to date. Since there is such a wide range, the different viruses in this group are classified according to categories. They are classified mainly according to their potential to cause cancer, according to the degree of risk they pose, whether it be high or low.
How could you contract it?
HPV is so common that, in fact, most of the population will become infected over the course of their lifetime. The warts it causes, which appear on the fingers and palms, are frequent in children, and are typically associated with humid environments such as swimming pools, changing rooms, etc.
Almost all sexually active people will have contracted HPV at some point in their lives without even realizing it.
On the other hand, genital and oropharyngeal infections are transmitted mainly through sexual intercourse. In fact, the human papillomavirus is now considered the most common sexually transmitted infection.
Human Papillomavirus and Cancer
The link between HPV and cancer is very well known, and especially its relationship to cervical cancer. Now, let’s look at exactly how the virus is responsible for causing cancer.
HPV contains proteins that are capable of altering the process according to which cells multiply. These proteins are called E6 and E7. The E7 protein binds to pRb, a tumor suppression gene, and stops it from working, thus activating the cell cycle. On the other hand, E6 inactivates p53, which prevents tumor cells from being killed.
The joint action of both viral proteins (E6 and E7) results in uncontrolled cell proliferation.
Clinical Presentations of HPV
When the skin tissue becomes infected by the human papilloma virus (HPV), it causes the appearance of warts. The area of the body in which they appear depends on the type of human papilloma virus that the person encounters.
Although they can appear at any age and in any individual, they are especially common in children.
These warts usually have a rugged rounded appearance and grow outwards, with a convex shape. They are grayish or dirty white in color, and you will often see black dots in the center of them. These little black dots are actually the active virus.
They appear mainly on the fingers and palms, although they can also pop up on the elbows, knees, etc.
Verrucas are not usually painful, but they are contagious through direct contact with the affected area. That’s why we should pay special attention to children who bite their nails or the skin around them. Human papillomavirus 2 and 7 are the ones responsible for causing verrucas.
Plantar wart (“chicken eyes”)
These little warts appear on the soles of the feet, and possible to contract from swimming pools, showers, etc. Since they appear on the soles of the feet, which are responsible for supporting the whole weight of the body, they can be very painful. The culprits behind this type of symptom are human papillomaviruses 1, 2, 4, 27 and 57.
Mosaic warts begin with a set of fused warts, which are generally more superficial and less painful. They appear on the soles of the feet due to a human papillomavirus 3 infection.
This one is actually a genetic anomaly, which results in the immune system of sufferers being unable to fight or control HPV infections.
The result is the appearance of a large number of colored lesions (macules) and lesions with a bulbous appearance (papules). They most commonly appear on the palms of the hands and the fingers, and are the result of a human papillomavirus 5 and 8 infection.
Infections of the Non-Genital Mucosa
Here the contagion is, in the majority of cases, sexual. In fact, some experts on the topic consider say that the most common mode of transmission is specifically through oral sex.
Oral or Pharyngeal Papilloma
The human papilloma virus is also responsible for the appearance of lesions in the oral and pharyngeal mucosa. They are rough lesions, with the appearance of a blister and a dirty color.
There are certain types of virus that are “high risk.” These are most likely to cause the onset of cancer. This symptom appears mainly at the back of the tongue, in the tonsils or at the top of the throat.
Infections of the Genital Mucosa
In some cases, the HPV virus can cause the appearance of genital warts. These begin with types 6 and 11. While they may be very annoying, they are painless and have no risk of causing cancer.
The main problem lies in the high-risk strains of HPV: 16 and 18. And although these are the two types that relate to cancer, in reality there are up to a dozen of them. The type of cancer most related to HPV is cancer of the cervix. However, it can also cause cancers in the vagina, vulva and penis.
- Papanicolau test: this tests helps the diagnosis of cervical cancer. It is a vaginal cytology that detects precancerous cells, through a laboratory analysis of a sample.
- Human papilloma virus test: this uses molecular biology techniques to detect the DNA of the virus. This test is used to determine whether or not a person has been infected by a high-risk strain of HPV.
- Vaccination: Currently, most HPV vaccination campaigns target girls who are 12 – 13 years old. The vaccine protects against the higher-risk strains of the virus.
- Barrier methods of contraception.
There is currently no specific treatment for human papillomavirus. In 90% of cases, the body’s immune system will naturally eliminate any remaining traces of the virus within two years.
However, if you’re looking to get rid of the symptoms, cryotherapy is one of the better treatments for warts, and consists of applying liquid nitrogen to the lesions. Once you’ve undergone cryotherapy, it is a good idea to cover the lesions with a patch, or apply salicylic acid drops to them, until they disappear completely.
You can find more information about the relationship between human papillomavirus infection and oropharyngeal cancer here.