It is not possible to reliably diagnose HIV infection or AIDS based on symptoms alone. HIV symptoms are very similar to the symptoms of other illnesses. So the only way to know for sure whether a person is infected with HIV is for them to have an HIV test.
People living with HIV may feel and look completely well but their immune systems may nevertheless be damaged. It is important to remember that once someone is infected with HIV they can pass the virus on immediately, even if they feel healthy.
HIV is the virus that causes AIDS. If a person infected with HIV does not take effective antiretroviral treatment, over time HIV will weaken their immune system, which will make them much more vulnerable to opportunistic infections.
Symptoms caused by opportunistic infections
Opportunistic infections are caused by germs that are around us all the time but which can normally be fought off by a healthy immune system. Once the immune system is sufficiently weakened, such infections will develop and produce any of a wide range of symptoms. Some of these symptoms can be very severe. Certain cancers also become more common when the immune system is weakened.
Such symptoms, however, cannot themselves be interpreted as definite signs of HIV infection or AIDS. A diagnosis of AIDS requires signs of severe immune deficiency, which cannot be explained by any factor except HIV. This generally requires an HIV test.
Symptoms following HIV infection
Some people who become infected with HIV do not notice any immediate change in their health. However, some suffer from a brief flu-like illness within a few weeks of becoming infected, or develop a rash or swollen glands. These symptoms do not indicate the development of AIDS, and the symptoms usually disappear within a few days or weeks.
"I have flu-like symptoms/swollen glands - could it be HIV?"
Many illnesses have flu-like symptoms or cause swollen glands. You cannot have HIV unless you have been directly exposed to the virus. HIV can be transmitted during sexual intercourse with an infected person, through contact with infected blood or breastmilk, or during unsafe injections or medical procedures. If you are not sure whether or not you have been at risk of HIV then read our page about how you can and can't be infected with HIV.
The only way you can find out whether or not you have been infected is to have an HIV test.
