Kaposi's Sarcoma: Symptoms, Causes & Treatment Guide
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
Kaposi's sarcoma is a type of cancer that forms in the lining of blood vessels and lymph vessels, producing cell growths called lesions that often appear as pink, red, purple or brown spots on the face, arms and legs. The cause is infection with human herpes virus 8 (HHV-8), a virus that a healthy immune system normally controls; it turns dangerous when immunity weakens. There are four recognized types tied to HIV, organ transplant medicines, age and geography. Diagnosis rests on a skin biopsy, plus scans or scopes if the cancer may involve the lungs or digestive tract. There is no cure, but many treatment options — antiviral therapy, medicine adjustments, surgery, freezing, radiation and chemotherapy — can control it, and some people need no immediate treatment at all.
Quick Answer
What is Kaposi's sarcoma? A cancer that forms in the lining of blood vessels and lymph vessels, creating growths called lesions, usually on the skin.
What does it look like? Raised or flat growths on the skin that look pink, red, purple or brown, most often on the face, arms or legs.
What causes it? Infection with human herpes virus 8 (HHV-8), which usually stays harmless until a weakened immune system loses control of it.
Who is at risk? People with HIV, adults aged 50–70, people living in the Mediterranean, Eastern Europe and sub-Saharan Africa, and transplant recipients on immune-suppressing medicines.
How is it diagnosed? A skin biopsy of a lesion confirms it; endoscopy, colonoscopy, CT scans, chest X-rays or bronchoscopy look for internal involvement.
Is there a cure? No — but many treatment options can control it, and some people only need monitoring at first.
When should I see a doctor? Any new, changing, or unexplained skin growth — especially red, purple or brown spots — deserves a prompt medical evaluation.
What Is Kaposi's Sarcoma?
Kaposi's sarcoma is a type of cancer that forms in the lining of blood vessels and lymph vessels. The cancer forms growths of cells, called lesions, on the skin. The lesions often form on the face, arms and legs, and they may look pink, red, purple or brown.
Lesions also can appear on the genitals or in the mouth. In severe Kaposi sarcoma, lesions can develop inside the digestive tract and lungs — areas you cannot see.
The cause of Kaposi sarcoma is infection with the virus human herpes virus 8, also called HHV-8. In healthy people, this infection usually causes no symptoms because the immune system keeps it under control. In someone with a weakened immune system, however, HHV-8 can lead to Kaposi sarcoma.
The Four Types of Kaposi's Sarcoma
Kaposi's sarcoma is not one single disease experience. Healthcare professionals recognize four types, each tied to a different reason the immune system becomes vulnerable.
AIDS-related (epidemic) Kaposi sarcoma: Affects people infected with HIV, the virus that causes AIDS. It is the most common type; severity has dropped sharply with modern antiviral medicines.
Transplant-associated (iatrogenic) Kaposi sarcoma: Affects people taking medicines to control the immune system after an organ transplant. “Iatrogenic” means caused by medical treatment.
Classic Kaposi sarcoma: Affects older adults of Eastern European, Mediterranean and Middle Eastern descent. Usually grows slowly; can cause swelling in areas such as the legs.
Endemic Kaposi sarcoma: Affects young people in Africa. Can grow slowly on the skin or quickly inside the body.
Understanding which type applies to you matters, because treatment is matched to the type — as we cover later in this guide.
What Are the Symptoms of Kaposi's Sarcoma?
Kaposi sarcoma signs and symptoms center on the skin — but not always.
Skin lesions: the main sign
The two hallmark signs are a growth on the skin that may be raised or flat, and a growth on the skin that looks red, purple or brown in color.
The growths, called lesions, most often happen on the face, arms or legs. They usually don't cause discomfort.
If Kaposi sarcoma isn't treated, the lesions can get bigger. They may cause swelling in the lower legs caused by blood flow problems, enlarged lymph nodes, and skin that appears red or purple in color and may be painful and itchy.
Internal lesions: the signs you can't see
Kaposi sarcoma also can affect areas you can't see. It can grow in the digestive tract or lungs. When it happens in the digestive tract, symptoms may include diarrhea, nausea, stomach pain, vomiting and weight loss.
Raised or flat skin growth: on the face, arms, legs — sometimes genitals or mouth.
Red, purple or brown coloring: in the lesion itself; sometimes surrounding skin.
Lower leg swelling: caused by blood flow problems.
Enlarged lymph nodes: lumps near lesions or in drainage areas.
Painful, itchy red-purple skin: around or beneath existing lesions.
Diarrhea, nausea, stomach pain: signs of digestive tract involvement.
Vomiting, weight loss: also signs of digestive tract involvement.
When to see a doctor
Make an appointment with a doctor or other healthcare professional if you have symptoms that worry you. Any new, changing, or unexplained skin growth — particularly one that is red, purple or brown — is worth showing to a professional without waiting.
What Causes Kaposi's Sarcoma?
The human herpes virus 8 causes Kaposi sarcoma. Healthcare professionals believe this virus, also called HHV-8, spreads from person to person through saliva. It also may be passed through blood.
The key detail many people find reassuring: HHV-8 infection alone is usually not enough. When a healthy person gets the HHV-8 virus, that person's immune system is likely to control it. The virus may stay in the body, but it doesn't cause any problems. If something happens to weaken the immune system, the virus may no longer be controlled. This can lead to Kaposi sarcoma.
In other words, Kaposi sarcoma is a two-part story — the virus plus a vulnerable immune system. That is why it concentrates in specific groups of people.
Risk Factors for Kaposi's Sarcoma
Risk factors for Kaposi sarcoma include the following four.
HIV infection: HIV is the virus that causes AIDS; this type is the most common worldwide.
Older age: Kaposi sarcoma can happen at any age, but it's most common in adults between 50 and 70.
Living in certain parts of the world: it's rare in the United States; most common in the Mediterranean, Eastern Europe and sub-Saharan Africa.
Medicines that weaken the immune system: immune-suppressing medicines are often used after organ transplant surgery.
Notice that geography and age map directly onto the classic and endemic types described earlier. Each risk factor is essentially a window into why the immune system may lose control of HHV-8.
How Is Kaposi's Sarcoma Diagnosed?
Skin biopsy: the key test
A healthcare professional may recommend removing a small piece of a skin lesion for testing. This procedure is called a skin biopsy — a small tissue sample taken from the lesion and sent to a lab, where lab tests look for signs of cancer.
A skin biopsy can confirm Kaposi sarcoma.
Looking for cancer inside the body
Other tests might be needed to look for Kaposi sarcoma in the lungs or the digestive tract.
Skin biopsy: A small piece of a skin lesion is removed and tested in a lab.
Fecal occult blood test: Detects hidden blood in the stool (digestive tract); if positive, further tests find the source.
Endoscopy: A thin tube (endoscope) passes through the mouth so a professional can look inside the esophagus, stomach, and first part of the small intestine.
Colonoscopy: A thin tube (colonoscope) passes through the rectum to view the colon walls.
CT scan: X-rays create detailed images of the abdomen, pelvis, chest — the digestive tract or lungs.
Chest X-ray: May show something unusual in the lungs; if so, a CT scan or bronchoscopy follows.
Bronchoscopy: A thin tube (bronchoscope) passes through the nose or mouth into the lungs to view the airway lining and take tissue samples.
The pattern is straightforward: a skin lesion gets tested first, and internal testing only happens when there is a reason to suspect the cancer has gone deeper.
How Is Kaposi's Sarcoma Treated?
There's no cure for Kaposi sarcoma. But there are many treatment options that can help control it. Some people may not need treatment right away. Instead, the condition might be monitored to make sure it's not getting worse.
Treatment depends on the type of Kaposi sarcoma, the number of lesions and where they are, the effects of the lesions (such as causing pain or getting in the way of eating or breathing), and your overall health.
Treatment for AIDS-related Kaposi sarcoma
Thanks to better antiviral medicines to treat AIDS and ways to prevent it, Kaposi sarcoma has become less common and less severe in people with AIDS.
Taking antiviral medicines can lower the amount of the virus that causes HIV/AIDS and make the immune system stronger. This might be the only treatment needed for Kaposi sarcoma.
Treatment for transplant-related Kaposi sarcoma
Some people with transplant-related Kaposi sarcoma may be able to stop taking the medicines that are controlling the immune system, or switch to another medicine.
Treatment for small skin lesions
Treatments for small skin lesions might include minor surgery (also called excision), freezing treatment (called cryotherapy), radiation therapy, an injection of the chemotherapy medicine vinblastine into lesions, or applying a medicine cream or gel to the skin.
One point to know going in: lesions treated in any of these ways are likely to return within a couple of years. When this happens, treatment often can be repeated.
Treatment if there are many skin lesions
If Kaposi sarcoma causes many skin lesions, other treatments might be needed.
Radiation therapy uses powerful energy beams to kill cancer cells. This is a treatment option if there are many skin lesions, but not enough to need chemotherapy.
Chemotherapy uses strong medicines to kill cancer cells. It might be an option when Kaposi sarcoma affects multiple parts of the body. For Kaposi sarcoma that's getting worse quickly, chemotherapy might help.
Watchful monitoring: no immediate treatment needed; condition is tracked to make sure it's not worsening.
Antiviral medicines: for AIDS-related Kaposi sarcoma — often the only treatment needed.
Adjusting or stopping transplant medicines: for transplant-related Kaposi sarcoma.
Excision (minor surgery): for small skin lesions.
Cryotherapy (freezing): for small skin lesions.
Radiation therapy: for small or many skin lesions — when chemotherapy isn't needed yet.
Vinblastine injection: chemotherapy injected directly into lesions.
Medicine cream or gel: applied topically for small skin lesions.
Chemotherapy: for many lesions, multiple body areas, or fast-worsening disease.
Living with Kaposi's Sarcoma: What to Expect
It is completely understandable to feel unsettled by a cancer diagnosis — especially one with no cure. But it is worth holding onto the practical reality: treatment options are numerous, they are matched to your specific situation, and in the AIDS-related form, modern antiviral medicines have made the disease both less common and less severe than it once was.
Support communities for people living with sarcoma exist and can help you connect with others facing the same diagnosis. Your care team can point you toward local and online options.
Preparing for Your Appointment
Start by seeing a doctor or other healthcare professional if you have any symptoms that worry you. If your health professional thinks you might have Kaposi sarcoma, you might need to see a specialist. Specialists who care for people with Kaposi sarcoma include infectious disease specialists (doctors who treat conditions caused by infections), dermatologists (doctors who treat skin conditions), and oncologists (doctors who treat cancer).
What you can do
When you make the appointment, ask if there's anything you need to do in advance. Make a list of your symptoms, including when you noticed the skin growth and how it may have changed over time. Include key personal information such as your medical history, recent life changes and family medical history. List all medicines, vitamins or other supplements you take, including the doses. And bring your questions.
You may want to bring a friend or family member along to help you remember the information you're given.
Some basic questions worth asking:
What's likely causing my symptoms?
Other than the most likely cause, what are other possible causes for my symptoms?
What tests do I need?
Does my condition have a cure?
What's the best course of action?
I have these other health conditions — how can I best manage them together?
Should I see a specialist?
Are there brochures or other printed material I can have, and what websites do you recommend?
What would happen if I choose not to have treatment?
Don't hesitate to ask other questions.
What to expect from your doctor
Your healthcare professional may ask questions about your symptoms, such as when your symptoms began, how severe they are, what seems to improve them, and what appears to worsen them.
Conclusion
Kaposi's sarcoma is a rare but important cancer to understand. It starts with a common virus — HHV-8 — that most people's immune systems handle without ever knowing. The danger emerges when immunity weakens, which is why the four types map so clearly onto HIV, transplant medicines, age, and geography.
The practical takeaway is empowering: the skin signs are visible and identifiable, diagnosis starts with a simple biopsy, and treatment is adaptable — from antiviral medicines alone, to medicine adjustments, to surgery, freezing, radiation and chemotherapy. There is no cure, but there is real control, and for some people, no immediate treatment at all.
If you have noticed a new or changing skin growth — especially one that is pink, red, purple or brown — make an appointment with a healthcare professional. The earlier Kaposi's sarcoma is caught, the more options you have.
Frequently Asked Questions
What does Kaposi's sarcoma look like?
It appears as a growth on the skin that may be raised or flat, and looks red, purple or brown. The lesions most often form on the face, arms or legs, and they usually don't cause discomfort at first.
What causes Kaposi's sarcoma?
The human herpes virus 8 (HHV-8) causes Kaposi sarcoma. It is believed to spread through saliva and possibly blood. In healthy people the immune system keeps it under control; a weakened immune system can allow it to lead to Kaposi sarcoma.
Is Kaposi's sarcoma contagious?
The virus behind it, HHV-8, can pass between people through saliva and possibly blood. But most people who carry HHV-8 never develop Kaposi sarcoma — a weakened immune system is also required.
Is Kaposi's sarcoma a form of AIDS?
No. AIDS-related (epidemic) Kaposi sarcoma is one of four types and occurs in people infected with HIV. It is a cancer that can develop as a complication, not the definition of AIDS itself. Modern antiviral medicines have made this type less common and less severe.
How is Kaposi's sarcoma diagnosed?
A skin biopsy — removing a small piece of a skin lesion for lab testing — can confirm Kaposi sarcoma. If internal involvement is suspected, tests such as endoscopy, colonoscopy, CT scans, chest X-rays or bronchoscopy may be used.
Can Kaposi's sarcoma affect internal organs?
Yes. In severe cases, lesions can develop in the digestive tract and lungs. Digestive tract involvement may cause diarrhea, nausea, stomach pain, vomiting and weight loss.
Is there a cure for Kaposi's sarcoma?
There's no cure. But there are many treatment options that can help control it, and some people may only need monitoring at first.
Does Kaposi's sarcoma come back after treatment?
Lesions treated with excision, cryotherapy, radiation, vinblastine injections or topical medicines are likely to return within a couple of years. When this happens, treatment often can be repeated.
References
Kaposi sarcoma — Symptoms and causes (Published Jan. 03, 2025)
Kaposi sarcoma — Diagnosis and treatment (Published Jan. 03, 2025)
Rinnit.com provides general health information for educational purposes. This content does not replace professional medical advice — always consult a qualified healthcare provider for diagnosis and treatment.
Health information, not medical advice. This article is for general education and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your own health, and seek emergency care for urgent symptoms.
Comments