How do you know if someone has HIV?

It's hard to tell. Most people don't know that they have HIV. It can take up to three months before it shows up on a blood test. Sometimes it can take years before a person finds out. Some people only find out if they start getting sick a lot more often and go to a doctor to find out why. This is why it is important to see your doctor regularly and talk about things you are doing that may put you at risk of getting HIV. If you don’t have a doctor and are concerned that you may have HIV or other sexually transmitted infections, you can go to a local clinic and get tested. You can get tested for HIV anonymously as well. This means that no one will know the results of your HIV test but you and the clinic testing you (and they will not tell anyone).

You can't tell whether someone has HIV just by looking at them.