Anal warts and HPV: what they are, symptoms and causes

Anal warts and HPV

  • Anal warts and HPV: what are they?
  • Anal warts symptoms
  • Diagnosis
  • What causes anal warts?

Anal warts and HPV: what are they?

Anal warts

Anal warts, also known as anal condylomas, are benign lesions caused by the HPV virus.

These lesions may appear both in the area around the anus and in the genital area. At first, they look like small brownish spots that can be felt when touched.

However, condylomas tend to increase in size progressively and alter until they become growths that appear with stocks, which, if left untreated, tend to increase in number.


Human Papilloma Virus is a sexually transmitted virus that can cause abnormalities of the skin and the mucous membranes, especially around the genitals, including condylomas.

Specific strains of the virus can lead to genetic alterations in the cells of the inner lining of body in different areas which may degenerate over time. These alterations may cause tumors around the anus, the mouth and throat, cervical carcinoma and tumors on the penis. In this case, the infected HPV cells increase and become more and more resistant, replacing the healthy tissue in the areas affected.


Anal warts symptoms

Condylomas show as lesions of various colors, shapes and sizes which appear mainly on the genitals and around the anus. But, particularly in immunocompromised people, condylomas may also appear within the oral cavity and around the mouth.

Initially, the lesions are small, raised, brownish spots that are often painless. These patches may change color and form and turn into growths that may look like stalks or the head of a cauliflower. Such growths may be isolated or grouped together in one area.

The lesions then tend to spread and multiply. At this stage, there may be itching around the affected areas.

As already mentioned, condylomas are caused by the HPV virus. In most subjects, HPV is symptomless and goes away on its own but in some cases, it may play a significant role in cancer development. The Human Papilloma Virus is the cause of around 5% of tumors worldwide and, on average, a tumor caused by HPV is diagnosed every 8 seconds.



The presence of the HPV virus in the anal canal is initially diagnosed with a Pap Test, a painless exam during which a few cells are taken from the anal canal with a special brush. This exam allows the detection of the virus and the genotype without the need for a biopsy.

Testing of the samples taken provides the ability to confirm or exclude the presence of HPV and, if the test is positive, to identify the strain of the virus. Some strains of the virus are more likely than others to cause simple condylomas to develop into anal cancer (strain 16 and 18 are responsible for over 90% of all anal cancers).

If the anal Pap Test shows the presence of HPV, the specialist may request a High-Resolution Anoscopy (HRA), an examination that enables him or her to identify further lesions caused by the HPV virus, even in the very early stages.


What causes anal warts?

Anal warts are a highly contagious sexually transmitted disease caused by HPV (Human Papilloma Virus). 

The HPV virus is one of the most widespread sexually transmitted diseases (STDs) worldwide. It develops through direct contact with the skin or mucous membranes of an infected partner during anal, vaginal or oral sex. Towels and underwear may also spread the virus, although this means of infection is much less common.

The HPV virus can alter cells and lead to the formation of lesions on the skin and mucous membranes, especially around the genitals, including condylomas. Some strains of the HPV virus are termed “high risk” as they increase the risk of cancer.

Normally our immune system is able to fight the virus and block the formation of lesions that may lead to the appearance of tumors.

Yet, in some people the immune system is so weak that it is unable to fight the virus which, at times, may be very aggressive and spread quickly. Immunocompromised patients are at greater risk of contracting the HPV virus and anal condylomas.

The most common cause of immunosuppression is the HIV virus. The weakening of the immune system may also be due to other causes including chemotherapy, chronic infections, blood diseases, and organ transplants.