What’s the Difference Between STD and STI?

“STI” stands for sexually transmitted disease, while “STI” is short for sexually transmitted infection. You probably already knew that, and you are hoping to find out whether there is any functional or practical difference between the two terms. The answer is more complicated than it appears at first glance, primarily because not everyone in the medical field agrees. This article will explain the difference between STI and STI.

Diving Deeper: What Exactly Are Diseases and Infections?

Infection vs. disease

• Think of an infection as the first step on the road to disease. Infections haven’t yet turned into disease and often don’t cause any symptoms.
• This is actually why many experts are pushing to use STI over STD, and believe “STI” is misleading.
• “Disease” suggests that a person has a medical problem with obvious signs and symptoms. That’s often not the case at all since the most common STIs — like chlamydia and gonorrhea — are often asymptomatic.
• Another major difference between STIs and STIs is how they present. Because an STI is the later stage of an STI, you may have some symptoms. With an STI however, many carriers show no signs of being infected.

 

All STDs start as STIs

• Not all diseases start as infections, but when it comes to sexually transmitted ones, they do.
• Infections occur when pathogens like viruses, bacteria, or parasites enter your body and start to multiply. How they get into your body depends on the type of pathogen.
• Some get in through skin-to-skin contact with a person who has an infection; others are transmitted through an exchange of bodily fluids, like semen, vaginal secretions, or blood.
• Infection progresses to disease when these pathogens cause damage to your cells, and signs and symptoms appear.

But not all STIs develop into STIs

• Some STIs never develop into STIs. Take HPV, for example.
• HPV usually clears up on its own without causing any health problems. In these cases, HPV is an STI.
• If the infection doesn’t clear on its own, it can cause genital warts or certain cancers. This then makes it a disease.

Find STI testing near you and get care early * Prices and free services vary by provider. Please check the details before booking. Find STI testing → 01

Common Symptoms of STIs and STIs

No two STIs or STIs are the same, but some have very similar symptoms. Common symptoms to watch out for include:

• Unusual discharge from the vagina or penis
• Pain while urinating
• Painful blisters around the genitals
• Fleshy growths around the genitals
• Tingling or itching around the genitals
• In men, pain in the testicles
• In women, pain in the pelvis or abdomen
• In women, irregular periods or bleeding after sex
• Two infections which have slightly more unusual symptoms are syphilis and HIV. The primary symptoms of syphilis can include one or more painless sores on the genitals, a rash and flu-like symptoms. The primary symptoms of HIV can include flu-like symptoms and a red rash across the body.
• Pubic lice and scabies, while not STIs or STIs in the strictest sense, are commonly spread through sexual contact and can cause genital itching, a rash, spots of blood on your genitals, and black spots in your underwear.
• It’s also very important to understand that not all STI and STI initially present with symptoms – in fact up to 70% of women don’t experience symptoms when infected with chlamydia. For that reason, you should get tested after any episodes of sex without a condom, even if you’re asymptomatic.

When to get tested

• have had sex without a barrier method, like a condom
• have had or are planning to have sex with a new partner
• have multiple sexual partners
• are worried you may have been exposed to an STI
• are pregnant
• share injection drug equipment

How Many Types of Results Are There?

There are two types of results.

Negative Result

If you receive a negative result, stay on top of screening with regular STI testing.

Ask your healthcare provider about the best screening schedule for you based on your individual risk factors. You can also talk to them about the best ways to reduce your risk for STIs, like using barrier methods or PrEP.

Concerned about an exposure or symptoms? Get an STI test * Prices and free services vary by provider. Please check the details before booking. Find a testing service → 02

Positive Result

If you receive a positive result, your healthcare provider will prescribe a treatment or management plan depending on the diagnosis.

You’ll also need to notify your partner(s) so they can be tested and treated if needed. Not sure how to tell them? We’ve got you! This guide can help.

The most common STIs are caused by bacteria. A course of antibiotics can usually cure them.

Antibiotics don’t work on infections caused by viruses. Some viral infections clear on their own, but most are long-term conditions. Antiviral medications can usually manage symptoms and reduce the risk of transmission.

For STIs like crabs, which are caused by something other than bacteria or viruses, topical and oral medications usually do the trick.

Retesting might be recommended to make sure the treatment has worked.

How can I protect myself from STIs and STIs?

Only abstaining from sex (abstinence, or not having sex) offers complete protection from STIs. If you are sexually active, make sure to:

• Use a latex condom whenever you have any kind of sex. Condoms are especially important if you have multiple sex partners.
• Have sex with one person (monogamy). Or limit the number of sexual partners. Each new partner raises your risk of catching an STI.
• Choose sex partners carefully. Don’t have sex if you suspect your partner has an STI.
• Get checked for STIs regularly. Doing so helps prevent spreading the infection to other people. And ask any new sex partner to get tested before having sex for the first time.
• Avoid alcohol or drugs before having sex. People who are drunk or high may engage in risky sexual behaviors, which can lead to an STI.
• Learn the signs and symptoms of STIs. If you notice symptoms, get treatment quickly.
• Educate yourself about STIs. The more you know, the better you can protect yourself and your partners.

If I have an STI or STI, how can I prevent spreading it to others?

Take steps to protect yourself and others:

• Don’t have sex until you see a healthcare provider and receive treatment. You can resume sex when your healthcare provider says it’s OK.
• Follow your healthcare provider’s instructions for treatment.
• Return to your healthcare provider to get rechecked.
• Be sure your sex partner or partners also receive treatment.
• Use condoms whenever you have sex, especially with new partners.

Conclusion

Not getting an STI test means remaining unaware of the presence of the infection. Therefore, that ultimately also increases the risk of transmitting it to other people. This may explain why more and more health organizations have trended toward embracing the term STI over STD in more recent years.

Verified references

Links and relevance to the article’s main topic were reviewed on 13 August 2026. Each source supports only the scope stated in the original document and does not replace personalised medical, legal, or service advice.

1. CDC: About Sexually Transmitted Infections Accessed 13 August 2026
2. CDC: STI Treatment Guidelines Accessed 13 August 2026