What is an STD? | Common STDs | Symptoms | Risk Factors | Are STDs Curable? | Prevention | Testing

What are STDs?

STD stands for sexually transmitted disease. STDs are infections that are most often spread through vaginal, anal, and/or oral sex, but they can also be contracted from nonsexual contact like intravenous needle use, childbirth, breastfeeding, and skin-to-skin contact.

STDs are extremely common. According to the Centers for Disease Control and Prevention (CDC), it’s estimated that 20 million STD cases occur each year in the United States,1 and according to the World Health Organization (WHO), there are more than 1 million STIs acquired every day worldwide.2

STDs may not always show symptoms, but even if no symptoms are present, they can still cause irreversible damage. STDs can be scary, but most can be treated easily, especially if they’re caught early.

Take Charge of Your Health

At least 50% of the time, chlamydia​ ​has​ ​no symptoms​ in men and women which contributes to the disease being extremely common​ ​and​ ​easily​ ​spread​. It can be easily cured with antibiotics; get tested today if you think you may have been exposed.

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Most Common STDs?


Chlamydia is a curable bacterial infection and, according to the CDC, it’s the most common notifiable disease in the United States.3 Often chlamydia doesn’t show symptoms, so people do not seek testing. But if left untreated, chlamydia can lead to pelvic inflammatory disease (PID) and infertility. Learn more about chlamydia here.


Gonorrhea is a curable bacterial infection that tends to inhabit moist, warm places like the urethra, rectum, throat, genital tract, and reproductive tract.4 Often it doesn’t show symptoms, but it can still be passed with no symptoms present. Gonorrhea and chlamydia are typical co-infections, which means that it’s likely to acquire both at the same time. Learn more about gonorrhea here.


Syphilis is a curable bacterial infection that tends to go unreported because its symptoms are often absent or indistinguishable. Syphilis has four stages: primary, secondary, latent, and tertiary. In its early stages, syphilis is the most infectious and the least noticeable. It becomes more apparent in its final stages, which can result in damage to the brain and other organs.5 Learn more about syphilis here.


The human papillomavirus (HPV) is the most common STD. The CDC estimates that nearly every sexually active person will obtain at least one strain of the virus during their lifetime.6 There are over 100 different strains of HPV, most of which the body can fight off on its own. However, a few strains of HPV can cause genital warts or are considered “high-risk” and can lead to cancer. The HPV vaccine can prevent damaging strains of HPV. Learn more about HPV here


Herpes is caused by the herpes simplex virus (HSV). The virus is most known for causing cold sores/fever blisters on the face and genital region. Herpes spreads through sharing infected fluids, skin-to-skin contact, and contact with cold sores. The virus can spread even when cold sores are not present;7 over half of the population has it;8 and though there is no cure, it can be managed with treatment. Learn more about HSV-1 (oral herpes) or HSV-2 (genital herpes).


Hepatitis is a contagious liver disease that causes inflammation of the liver. Hepatitis A is typically caused by eating or drinking items contaminated with infected fecal matter. Hepatitis B and C usually occur as a result of contact with infected bodily fluids. Hepatitis may resolve through rest, replenishing fluids, and, in chronic cases, it can be treated with antiviral medications.9 There are also vaccines available to prevent some strains of hepatitis. Learn more about Hepatitis A, Hepatitis B or Hepatitis C.


The human immunodeficiency virus (HIV) attacks the immune system, weakening the body’s ability to fight off other infections and making the body highly vulnerable to major illnesses. HIV is a lifelong disease, but it can be managed with antiretroviral (ART) medication. If it’s not managed, it can progress into acquired immunodeficiency syndrome (AIDS), which is a chronic, potentially life-threatening condition.10 Learn more about HIV and AIDs.


Trichomoniasis or “trich” is the most common curable STD in the world, and it’s typically passed through vaginal sex. In the U.S., an estimated 3.7 million people have the infection, but only about 30% of people develop any symptoms. If symptoms are present, they include foul-smelling vaginal discharge, genital itching, and painful urination.11 Learn more about trichomoniasis here.

STD Symptoms

The biggest takeaway with STD symptoms is that the most common STD symptom is no symptom at all. STDs may or may not show symptoms, depending on the STD and how it reacts with your body. Many STDs share similar symptoms, which is why it’s not possible to diagnose an STD based on symptoms alone; you must get tested in order to receive an accurate diagnosis. That being said, here are some of the most common signs to look out for:

STD Symptoms in Men

STD symptoms in men include:

  • Painful urination
  • Itching, burning penis
  • Penile discharge
  • Bumps or blisters around the penis
  • Painful ejaculation
  • Tender, swollen testicles
  • Sore throat
  • Anal warts
  • Watery diarrhea
  • Rectal bleeding
  • Rectal discharge
  • No symptoms at all
STD Symptoms in Women

STD symptoms in women include:

  • Vaginal itching, burning, or discomfort
  • Vaginal discharge
  • Blisters in the genital area
  • Painful sex
  • Rash in the genital area
  • Painful urination
  • Sore throat
  • Anal warts
  • Watery diarrhea
  • Rectal bleeding
  • Rectal discharge
  • No symptoms at all

STD Risk Factors

Anyone who is sexually active is at risk of obtaining an STI. However, certain factors can increase your risk. These risk factors include: 12

  • Having unprotected sex—Unprotected sex is extremely risky for spreading STDs. Two people are directly exchanging sexual fluids is the most direct method for STD transmission. This is true for vaginal, anal, and oral sex.
  • Having sexual contact with multiple partners—More partners means more chances to get an infection. This is true for simultaneous partners as well as consecutive monogamous partners.
  • Having an STI—Having one STI makes getting others more likely. This is because the immune system is already weakened, inflammation and open sores make it easier for STDs to transfer, and certain activities that led to the first STD are likely to lead to more later on.
  • Abusing alcohol or recreational drugs—Abusing drugs and alcohol lowers your inhibitions and can make it more likely for you to engage in risky behaviors, such as unprotected sex.
  • Injecting drugs—If you inject drugs, be sure that you only use clean needles. Shared needles can lead to obtaining STDs, such as HIV and hepatitis.
  • Using dirty needles—Skin punctures from unclean needles (tattoos, body piercings, or certain invasive beauty trends) can transmit STDs like HIV and hepatitis.
  • Being between the ages of 15–24—Half of all STIs occur in people between the ages of 15 and 24. This is due to a combination of behavioral, biological, and cultural reasons, including the fact that the cells of a young woman’s cervix are highly susceptible to infection.13
  • Having anal sex—Anal sex causes a higher chance of tearing, which raises the likelihood that there will be an exchange of blood. In addition, the anal lining is thin, making it easier for viruses to spread.
  • Certain occupations—Careers in certain industries, such as healthcare and sex work, have a higher risk of exposure to blood-borne pathogens like HIV and hepatitis.

Are STDs Curable?

The following STDs can be cured with antibiotics:

  • Chlamydia
  • Gonorrhea
  • Syphilis
  • Trichomoniasis

The following STDs are typically cured naturally by the body and/or some strains can be prevented by a vaccine:

  • Hepatitis (A, B, C)
  • HPV

The following STDs are lifelong and can be managed with treatment:

  • Herpes I & II
  • HIV


The only 100% effective way to prevent STDs is to remain abstinent. However, because abstinence is an unrealistic expectation for most people, it’s necessary to take steps to protect your sexual health and reduce your risk. Here are a few preventative steps you can take:

  • Use protection—Using latex condoms and dental dams every time you have sex can help reduce your STD risk.
  • Get vaccinated—Getting vaccinated before having sex can prevent certain STDs.
  • Limit sexual partners—Having fewer partners or being mutually monogamous with someone who has tested negative can prevent infection.
  • Communicate with partners—Before having sex, talk to your partner(s) about STD status and testing.
  • Consider PrEP—Pre-exposure prophylaxis (PrEP) is an FDA-approved drug that reduces the risk of contracting HIV.
  • Avoid abusing alcohol or drugs—Being sober helps you make responsible decisions that can lower your risk of exposure.
  • Get tested regularly—Regular testing for STDs can help you know your status and get treatment if necessary.

STD Testing

There are multiple options for STD testing. Regardless of which you choose, routine STD testing is a necessary part of maintaining your sexual health. Testing can be done at free clinics, private doctor’s offices, online lab testing services, and mail-to-order kits. It can be performed using a urine sample, blood sample, and/or swab.  It’s necessary to choose an option for STD testing to ensure the sexual health of you and your partner(s). is an online lab testing service that provides STD testing through urine and blood samples. With our service, you can order a test online, visit a lab, and receive results in a few days.

  1. “CDC Fact Sheet: Information for Teens and Young Adults: Staying Healthy and Preventing STDs.” Centers for Disease Control and Prevention.
  2. “Sexually Transmitted Infections (STIs).” World Health Organization.
  3. “Chlamydia – CDC Fact Sheet (Detailed).” Centers for Disease Control and Prevention.
  4. “Gonorrhea.” Mayo Clinic.
  5. “Stages of Syphilis.” University of Michigan – Michigan Medicine.
  6. “Genital HPV Infection – Fact Sheet.” Centers for Disease Control and Prevention.
  7. “Genital Herpes – CDC Fact Sheet (Detailed).” Centers for Disease Control and Prevention.
  8. “Herpes Simplex Virus.” World Health Organization.
  9. “Hepatitis.” Healthline.
  10. “About HIV/AIDS.” Centers for Disease Control and Prevention.
  11. “Trichomoniasis – CDC Fact Sheet.” Centers for Disease Control and Prevention.
  12. “Sexually transmitted diseases (STDs).” Mayoclinic.
  13. “STDs in Adolescents and Young Adults.” Centers for Disease Control and Prevention.

Medically Reviewed by J. Frank Martin JR., MD on January 1, 2020

Written by Nick Corlis on December 22, 2019

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