STD stands for sexually transmitted disease and STI stands for sexually transmitted infection. An STD and STI is a disease or an infection caused by a parasite, bacteria or virus that spreads from one person to the other through sexual activities.
There are many STDs that go unnoticed because they do not display obvious signs and symptoms. This is the reason why medical organizations recommend STD tests once in a while.
The reason why STD diagnosis without an actual test can be confusing is because some of these infections will mimic other diseases or look like other STDs. Having a symptom that is in the list of STD symptoms does not necessarily indicate you have been infected with that STD. The best way to know if you have an STI or an STD is to get tested.
Some STDs can cause serious complications when left untreated even if there are no symptoms. Some of these serious health issues include pelvic inflammatory disease, organ damage, ,and in some cases death.
The CDC recommends routine STD tests especially for sexually active individuals even if there are no visible symptoms. Most STDs will not just affect the genital area; they will spread to the upper thighs, throat, mouth, eyes, anus, and organs.
Sometimes there might be a difference in symptoms in men and women.