Kaposi Sarcoma - Symptoms, Causes & Treatment
Medically reviewed by Dr. Anand S. Urhekar, MD, MD Pathology, Clinical Advisor · Last updated June 2026
A cancer of the cells lining blood and lymph vessels, caused by human herpesvirus 8 (HHV-8). It appears as purple, red, brown or almost black patches, plaques or nodules, most often on the legs, feet or face, and can also involve the mouth, lymph nodes and internal organs.
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Quick Answer
Kaposi sarcoma is a type of cancer that causes abnormal tissue to grow beneath the skin or in the lining of the mouth. It typically appears as multiple painless, purple, red, or brown patches and plaques, frequently starting on the legs. The condition is triggered by human herpesvirus 8 and occurs most often in individuals with a weakened immune system. Because these spots can resemble other harmless skin growths, it is crucial to have a healthcare professional evaluate them promptly to obtain an accurate diagnosis and appropriate medical care.
Symptoms
- Purple, red, brown or black patches that do not blanch
- Raised plaques or firm nodules, often on legs or feet
- Lesions inside the mouth or on the palate
- Swelling (lymphoedema) of the affected limb
- Usually painless, but can ulcerate or bleed
Causes & Risk Factors
- Human herpesvirus 8 (HHV-8) infection
- Advanced or untreated HIV infection
- Immunosuppression after organ transplant
- Older age with Mediterranean or Eastern European ancestry (classic type)
- Endemic form in parts of sub-Saharan Africa
Treatment & Management
- Antiretroviral therapy where HIV-related (often causes regression)
- Reducing immunosuppressive medication after transplant, under specialist advice
- Local radiotherapy or cryotherapy for isolated lesions
- Intralesional chemotherapy
- Systemic chemotherapy (liposomal doxorubicin, paclitaxel) for widespread or organ involvement
When to See a Doctor
See a doctor promptly about any new purple or dark patch or lump that persists, grows or bleeds — particularly if you are immunosuppressed or living with HIV. A biopsy is required to confirm the diagnosis.
Frequently Asked Questions
What do the initial spots of Kaposi sarcoma look like?
Kaposi sarcoma usually starts as flat patches on the skin that look purple, red, or brown. Over time, these spots can thicken into raised bumps or thicker plaques. Unlike common bruises, they do not turn yellow or fade over a few weeks. They often appear on the legs, face, or inside the mouth and are generally painless and not itchy, although swelling might occur in the surrounding areas.
How do you get Kaposi sarcoma?
This cancer is directly associated with a viral infection called human herpesvirus 8 (HHV-8). However, most people who carry this virus never develop the cancer. Kaposi sarcoma typically only develops when a person's immune system is significantly weakened. This immunosuppression can be due to conditions like advanced HIV infection, taking immune-suppressing drugs after an organ transplant, or as a natural decline in immunity in older populations.
Could my purple spot be a pyogenic granuloma instead of Kaposi sarcoma?
It is possible, but there are noticeable differences. A pyogenic granuloma is almost always a single, rapidly growing, bright red or purple bump that bleeds very easily. In contrast, Kaposi sarcoma usually presents as multiple purple-brown patches or plaques rather than a solitary bump, and it frequently appears on the legs or inside the mouth. A doctor will need to perform a biopsy to tell for sure.
Can Kaposi sarcoma be cured?
Treatment varies based on the underlying cause and the extent of the disease. While it is rarely completely cured, it can often be effectively managed. For those with HIV, starting or adjusting antiviral therapy can shrink the lesions significantly. Other treatments may include removing individual lesions, radiation therapy, or chemotherapy for widespread spots. Consistent medical care often leads to long-term control of the condition and normal daily functioning.
When should I see a doctor about a purple patch on my skin?
You should consult a doctor if you develop unexplainable purple, brown, or red patches that do not fade like a normal bruise after a couple of weeks. Urgent medical attention is required if these spots are multiplying rapidly, appear inside your mouth, bleed persistently, or are accompanied by unexplained swelling, fever, or breathing difficulties. Early medical assessment is critical whenever cancer is suspected.
Is Kaposi sarcoma contagious by touching someone's skin?
No, the cancer itself is not contagious. You cannot catch Kaposi sarcoma by touching the lesions of an infected person. While the underlying virus, HHV-8, can be transmitted through saliva or sexual contact, the virus alone does not usually cause the cancer in people with a healthy, fully functioning immune system. Normal social contact is entirely safe and poses no risk of developing the condition.
Are there ways to prevent Kaposi sarcoma from developing?
The most effective way to prevent Kaposi sarcoma is by maintaining a strong immune system. For individuals with HIV, staying strictly adherent to prescribed antiretroviral therapy prevents the immune suppression that allows this cancer to develop. For transplant patients, managing immunosuppressive medications closely with a doctor is essential. Safe sex practices can also lower the likelihood of contracting both HIV and the herpesvirus linked to the disease.
How can ScanSkinAI help me check for Kaposi sarcoma?
ScanSkinAI can analyze photos of your skin to help identify visual features that might be typical of Kaposi sarcoma, providing a preliminary risk assessment. However, it is fundamentally a screening aid and cannot diagnose cancer or any other medical condition. Because these lesions require a medical evaluation and often a biopsy, you must share any concerning results with a healthcare professional to get an accurate diagnosis.
Related Conditions
Medical References
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Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. The content on this page should not be used to diagnose or treat any health problem. Always consult with a qualified healthcare professional for proper medical evaluation, diagnosis, and treatment of your condition.