Areas of abnormal or damaged tissue, called lesions, are a common symptom of Acquired Immune Deficiency Syndrome (AIDS). There are several different types of AIDS lesions, caused by opportunistic infections and cancers that attack the sufferer as AIDS weakens his or her immune system. The most visible types of AIDS lesions are on the skin, but they can also appear in internal organs such as the brain and kidneys.
The cause of AIDS lesions best known to most of the general public is Kaposi's sarcoma, a form of cancer in the blood and lymph vessels caused by the Kaposi's sarcoma–associated herpesvirus. Most carriers of the virus are not affected by it, but in a person with a compromised immune system it can produce rapidly spreading malignant tumors in the victim's body. It is usually first visible as raised, darkened lesions on the skin, produced by distortion in the formation of blood vessels, but as it progresses it sometimes spreads into the mouth and inside the body. Other viral infections commonly seen in AIDS sufferers that cause cutaneous lesions include olluscum contagiosum and both oral and genital herpes simplex virus.
Other AIDS lesions appear in the nervous system. Toxoplasmosis, an extremely common protozoan infection that is harmless in most people but extremely dangerous to someone with a badly compromised immune system, can cause brain and eye lesions in people with AIDS. Another infection that is common and usually harmless in the general population that is dangerous to AIDS patients is progressive multifocal leukoencephalopathy (PML). PML causes lesions in the white matter of the brain that cause diminished motor control; changes in sight, speech, and personality; and eventually death in the absence of treatment. Another common cause of brain lesions in people with AIDS is a type of tumor called a primary central nervous system lymphoma, which can cause headaches, seizures, and dementia.
Other areas of the body can also develop lesions due to AIDS, its accompanying opportunistic diseases, or the side effects of AIDS medications. Advanced Kaposi's sarcoma can produce AIDS lesions inside the gastrointestinal tract, lungs, or lymph nodes. A significant percentage of AIDS sufferers are also infected with hepatitis C, which causes lesions of the liver and can also cause small skin lesions, usually on the legs. Anti-retroviral drugs, commonly used to slow the development of AIDS, can also cause liver damage when taken in high amounts or for extended periods of time. Some AIDS sufferers develop HIV-associated nephropathy, a condition that produces lesions on the kidneys and can eventually cause renal failure.