Kaposi sarcoma can sometimes cause skin lesions, which might be purple, red, or brown. These may have unwanted physiological and psychological effects.

In people with weakened immune systems, the human herpesvirus-8 can cause a form of cancer called Kaposi sarcoma.

This article focuses on Kaposi sarcoma lesions, including how they develop, their effects, outlook, and more.

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According to the American Cancer Society (ACS), Kaposi sarcoma begins in the cells that line lymph vessels and blood vessels.

As the cancer cells grow and multiply, they form tumors. These can develop in several possible organs:

Kaposi sarcoma can cause visible changes to the skin, such as blotches and growths. These are “Kaposi lesions.”

Kaposi lesions usually appear on the legs or face, although they could affect any part of the skin. They may have the following colors:

  • purple
  • red
  • brown

As a study in Clinical Diabetes and Endocrinology points out, Kaposi lesions may be less visible in people who have darker skin tones.

Kaposi lesions can take different forms, and develop in several locations. The pictures below highlight these variations.

Although Kaposi lesions can be asymptomatic, they may sometimes cause negative effects.

Some of these effects are physiological. As the ACS notes, certain Kaposi lesions develop on the legs. Others develop in the groin area. These lesions can cause painful swelling in the arms, legs, or feet.

Additionally, Kaposi sarcoma may cause lesions in the digestive tract, lungs, or liver, which can be life threatening. For example, lesions in the digestive tract could cause bleeding, and lesions in the lungs can cause difficulty breathing.

Kaposi lesions can also have psychological effects.

Generally speaking, there is evidence that skin diseases can lead to depression, anxiety, and loneliness.

In fact, people with skin conditions are at an increased risk of developing alcohol use disorder (AUD).

Scientists have documented several types of Kaposi sarcoma. This section details some of their differences.

Classic Kaposi sarcoma

As the National Cancer Institute (NCI) explains, classic Kaposi sarcoma is most likely to develop in older men. It is also especially prevalent in people of Italian or Eastern European Jewish origin.

In classic Kaposi sarcoma, lesions are most likely to develop on:

  • the legs
  • the ankles
  • the soles of the feet

These Kaposi lesions can become numerous over time. Often, the lesions themselves are asymptomatic.

Endemic or African Kaposi sarcoma

Endemic Kaposi sarcoma develops only in people who live in equatorial Africa.

According to the ACS, it is most common in people under 40 years of age. Its lesions can develop in any part of the skin.

Epidemic or HIV-related Kaposi sarcoma

Epidemic Kaposi sarcoma develops only in people living with HIV.

However, not everyone with HIV will develop this form of Kaposi sarcoma.

As the NCI explains, it can cause Kaposi lesions anywhere on the skin.

Iatrogenic or transplant-related Kaposi sarcoma

The ACS describes iatrogenic Kaposi sarcoma as any Kaposi sarcoma that forms due to an organ transplant.

Iatrogenic Kaposi sarcoma only occurs in people who have received a transplanted organ. Its lesions can also develop on any part of the skin.

According to a 2022 review, the cause of Kaposi sarcoma is always the human herpesvirus-8 (HHV-8). Through a largely unknown process, HHV-8 causes cancer cells to develop around the lymph nodes and blood vessels.

Not everyone with HHV-8 will develop Kaposi sarcoma. For this cancer to develop, individuals who have an HHV-8 infection must also be immunocompromised.

As the ACS explains, several factors could contribute to an individual becoming immunocompromised:

  • Classic Kaposi sarcoma: As an individual ages, their immune system may weaken.
  • Endemic Kaposi sarcoma: If an individual lives in equatorial Africa, they are more likely to have chronic infections and be malnourished. Both can weaken a person’s immune system.
  • Epidemic Kaposi sarcoma: If an individual has late-stage HIV, they can develop AIDS. AIDS is the final stage of HIV, and it can cause significant damage to a person’s immune system.
  • Iatrogenic Kaposi sarcoma: If an individual receives a transplanted organ, they may require immunosuppressing drugs. These drugs reduce the individual’s immune response so their body does not reject the transplant.

Treatment for Kaposi sarcoma aims to improve symptoms and delay the progression of the condition.

Healthcare professionals will monitor the lesions and closely follow their progression.

Doctors can treat the lesions using:

  • cryotherapy, where a healthcare professional freezes the lesions
  • laser treatments
  • intralesional injections, where a healthcare professional administers medication directly into lesions
  • surgery or curettage, where a doctor cuts away lesions

Doctors may also use treatments such as chemotherapy and radiation therapy, depending on the case. Some patients might receive two or more types of treatment simultaneously.

According to the ACS, treating Kaposi sarcoma can help reduce the lesions and stop them from progressing.

For people with AIDS, doctors may recommend highly active antiretroviral therapy (HAART). Many people with AIDS only need HAART to shrink lesions and keep them from progressing.

In organ transplant patients, medications called sirolimus and everolimus may control the lesions while preventing organ rejection.

Antiviral medications such as ganciclovir or foscarnet can help prevent new lesions from forming, but they cannot treat existing lesions.

Kaposi lesions can worsen if a person develops an infection. A doctor may recommend medication and lifestyle changes to reduce the chance of infection.

The outlook for people with Kaposi sarcoma varies.

Up to 20% of cases of classic Kaposi sarcoma are fatal. For other forms of Kaposi sarcoma, the outlook is more varied.

For instance, the outlook for people with iatrogenic Kaposi sarcoma will depend on whether they can tolerate lower doses of immunosuppressant drugs.

This section answers some frequently asked questions about Kaposi sarcoma lesions.

Do Kaposi sarcoma lesions go away?

Kaposi lesions do not go away on their own. However, the NCI notes that doctors can treat Kaposi sarcoma. This may reduce the size of the lesions and stop them from progressing.

The lesions may shrink with highly active antiretroviral therapy (HAART) in those with AIDS.

However, a doctor may not be able to completely remove Kaposi sarcoma lesions. They can prescribe antiviral medication to prevent new lesions from occurring, and some treatments can shrink existing lesions.

What can be mistaken for Kaposi sarcoma?

Scientists have documented many conditions that present like Kaposi sarcoma.

These include spindle-cell melanoma, cutaneous angiosarcoma, and acroangiodermatitis.

Kaposi sarcoma is a form of cancer. Although it begins in cells lining the lymph vessels and blood vessels, it can spread to various different organs.

This commonly includes the skin, where it may cause lesions. Kaposi lesions may be purple, brown, or red.

This condition arises from an HHV-8 infection, but only in immunocompromised people. At-risk groups for Kaposi sarcoma include older Mediterranean and Jewish people, people living in equatorial Africa, and people with HIV. People who have received organ transplants are also at risk.

The outlook for those with this condition varies with the underlying cause of the compromised immunity.