Warts are formations that are caused by human papillomaviruses (HPV). Discover the classification of these according to their characteristics.
As strange as it may seem, we can affirm, as a preface to all the information that we will expose you later, that warts are a direct cause ofinfection by a virus.
Despite being extremely common skin formations in the global population, it is exciting and at the same time complex to know their cause and distribution, since epidermal warts contain many surprises in a medical and epidemiological field.
So, today we condense in these lines the 7 types of warts and their characteristics. We encourage you to continue reading, because surely you will not see that wart that accompanies you since childhood with the same eyes when you finish reading.
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Human papillomavirus (HPV) and wart formation
Describing the types of warts without first knowing their etiology is as far-fetched as starting to build a house by the roof. Therefore, it is necessary to cement the foundations of its causative agent, even if it is in a simple way. Let’s get to it.
As we have previously told you, the culprit of these small lumps isthe human papillomavirus (HPV), a term that refers to various groups of DNA viruses belonging to thePapillomaviridae family, composed of a double strand of circular DNA about 8,000 base pairs in length and a protein capsid. These viruses occur with varying severity, from the formation of small, harmless warts to cervical cancer.
It should be noted that, from now on, we will refer to each strain with terms such as “HPV1”; “HPV30”, in general, “HPV”. This nomenclature is necessary to designate each specific type of papillomavirus, since it is estimated thatthere are about 200or more. The name of each of these viruses depends on the DNA sequence that conforms them, because the proteins of their capsid are so similar, the classification by serotypes is not useful in this viral family.
Once the causative agent has been defined, we present a series of data provided by the World Health Organization (WHO) and other sources, which contextualize the papillomavirus family in an epidemiological setting:
- It is estimated that there are more than 200 types of HPV, of which at least 40 affect the genital areas.
- Within all these types, at least 14 of them are high-risk oncogens. This means that they can promote the appearance of cancer.
- HPV 16 and HPV 18 are responsible for 70% of cervical cancer cases.
- In 2018, this resulted in the deaths of more than 300,000 women with this type of cancer.
Despite these exorbitant figures, it is essential to note that most genital HPVs in women disappear in a maximum of two years without apparent complications (90% of cases), but even so, when the infection recurs (between 5% -10% of women), precancerous lesions can develop into malignant tumors. This is the case of human papillomaviruses that affect the genital area, but epidermal warts, the formations that concern us today, are caused bymuch more harmless strains.
- We recommend you read: “Skin types: what is yours and how to take care of it?”
How are warts classified?
Once we have laid the foundations of HPVs and what they imply in society at a medical and epidemiological level, we are prepared to describe the types of warts and their characteristics.
1. Common warts
Several studies estimate that the prevalence of skin warts can reach up to22% in adolescent populationsand, without a doubt, this type of warts are the most common presentation.
In general, these formations are caused by HPV types 1, 2, 3, 4 and 7, and are characterized by oval papules with net edges. They measure from 2 to 10 millimeters in diameter, and are generallyasymptomatic (that is, they do not produce pain or discomfort in the patient). Finally, it is essential to emphasize that they can occur anywhere on the body, although their appearance is more common in the hands.
2. Flat warts
They are caused by HPVs 3, 10, 28 and 49 in general. Its presence is based on the appearance of flattened papules of normal skin color or pink and with a slightly scaly surface.
It should be noted that this type of warts appear byautoinoculation, that is, scratching in the patient that allows the entry of the virus into the epidermis. Therefore, its favorite place of appearance is on the marks of a wound or scratch or on the patient’s face. Like the previous ones, they are asymptomatic.
3. Filiform warts
Long, narrow warts that usually grow over theeyelids, face, neck, and lips. They are easy to treat, but the importance of these formations lies in their differential diagnosis. Unfortunately, cutaneous carcinomas can also take these forms, so you have to be careful and go to the doctor before the emergence of this type of warts.
4. Palmaplantar warts
The most common causative agent of this type of warts is usually HPV 1, although it is also caused by HPVs 2 and 4. As their name suggests, these warty forms appear on the soles of the hands and feet, and are characterized by an internalized papule shape covered by a keratinized epithelium.
Unlike the others, these wartsare usually painfuland bother the patient when standing. This type of formation can easily be confused with calluses, but palmoplantar warts have a differential characteristic: they have a series of black dots on their surface, which correspond to thrombosed dermal capillaries.
5. Periungual warts
In this case, warts are located on the nail plate, a structure that is part of the nail. They appear as thickened skin fissures, shaped like cauliflower and a whitish color of rough nature. Although they are usually asymptomatic, their treatment can be complicated by their elusive location (being somebelow the nail, the drug may not reach the site of action well).
6. Mosaic warts
We could say that these formations are widely related to palmoplantar warts, as these are nothing more than anassociation of small plantar wartsvery close to each other.
7. Genital warts
These warts occur as velvety papules, of net limits, flattened and with a broad base in various genital or areas. It should be noted that it is necessary to differentiate genital warts from mucous papillomas, as the latter differ from the rest because they invade and live on mucous cells, unlike skin warts, which settle on the epidermis. Even so, there are epidermal warts that can occur on the skin of the genitals, because as we have said, they are ubiquitous.
In the group of strictly genital mucosal HPVs we find the most problematic of all: HPV 16 and HPV 18. As we have said before, a woman with an adequate immune system should not worry, because90% of infections by these viruses are self-resolvingand disappear in a maximum of two years. Unfortunately, 5% to 10% of women are not so lucky, as they end up developing cervical cancer.
Conclusions
Despite this bitter ending, we want to emphasize that a wart on the arm has little or nothing to do with genital cancer. HPVs are a very extensive family of viruses and, as we have seen, they can present themselves in extremely different ways, being in most cases, harmless. So, the appearance of a non-painful wart without strange colorsshould not worry us. Of course, if it is painful, has very irregular shapes or raises suspicions, it is time to go to the doctor. Some formations such as melanomas (a type of cancer) can be confused with warts or moles.
As we have been able to read in these lines, the world of warts goes far beyond small lumps in any part of our body. If we discover that the causes of these are HPVs or human papillomavirus, it opens up an exciting medical and epidemiological range, but at the same time dangerous.
As we promised you at the beginning, surely this space has made you change, at least a little, the perception you had of warts until now. Of course, information like this highlights the multiple processes within our body that escape our eyes and understanding.
References
- HPV and HPV Testing, American Cancer Society. Collected on October 24 in https://www.cancer.org/es/cancer/causas-del-cancer/agentes-infecciosos/vph/vph-y-pruebas-para-vph.html
- Warts, integrative medicine, portal elsevier. Collected on October 24 at https://www.elsevier.es/es-revista-medicina-integral-63-articulo-las-verrugas-13013886
- Human papillomas (HPV) and cervical cancer, WHO. Retrieved October 24 in https://www.who.int/es/news-room/fact-sheets/detail/human-papillomavirus-(hpv)-and-cervical-cancer
- Warts, MSD Manuals. Collected on October 24 in https://www.msdmanuals.com/es/professional/trastornos-dermatol%C3%B3gicos/enfermedades-cut%C3%A1neas-virales/verrugas
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
