Learn All About Sexually Transmitted Diseases

Your sexual health is very important. In this article, you’ll discover the most common sexually transmitted diseases and how to prevent them.
Learn All About Sexually Transmitted Diseases
María Belén Del Río

Reviewed and approved by the doctor María Belén Del Río.

Last update: 27 December, 2022

Sexually transmitted diseases (STDs), also called venereal diseases or sexually transmitted infections (STIs), are a group of diseases that are transmitted through sex.

They can spread through contact with the genitals or through the exchange of bodily fluids (blood, semen, vaginal discharge…). Some of the causative organisms are bacteria, fungi, viruses, or parasites.

How to prevent sexually transmitted diseases

The only 100% safe way to avoid STD transmission is sexual abstinence. To reduce the risk of infection, you should use a contraceptive barrier method: the male or female condom.

Some STDs don’t cause symptoms until some time after infection. Thus, if you’ve have had risky sex, it’s important to contact a health professional to get the necessary diagnostic tests.

What’s risky sexual behavior?

Having sex (with or without penetration) without a contraceptive barrier method with a partner with an unknown state of health is considered risky.

How can I know my sexual health?

If you want to know your sexual health, the first thing to do is contact a trusted medical professional, such as your midwife or your gynecologist.

Some of the tests they may request in order to assess your sexual health are the following:

Learn All About Sexually Transmitted Diseases
  • Blood tests.
  • Vaginal and endocervical swabs (in women).
  • Urethral discharge culture (in men).

Types of sexually transmitted diseases


This isn’t exclusively an STD. It’s caused by the fungus Candida albicans, which is also naturally present in the female vaginal flora. It can occur when the protective vaginal flora is destabilized (due to stress, pregnancy, or immunosuppression, among other causes).

It has very characteristic symptoms:

  • Lumpy and whitish vaginal discharge.
  • Itching in the external genitalia.
  • Dysuria (painful urination).
  • Rashes on the external genitalia, especially in men.

This condition is diagnosed by a vaginal swab. Then, it’s treated with topical or oral antifungal drugs when the infections are recurrent.


The bacterium Chlamydia trachomatis causes this condition. It doesn’t cause characteristic symptoms. Thus, it can go unnoticed for quite some time. Also, the carrier can transmit it during unprotected sex.

Here are some of the possible symptoms that may occur:

  • Abnormal vaginal discharge.
  • Dysuria.
  • Dyspareunia (painful sexual intercourse).
  • Pelvic inflammatory disease (PID) in advanced stages.

Medical professionals diagnose this condition through endocervical swabs and urethral culture test. The patient must take antibiotics to treat it.

Genital herpes (HSV II), one of the sexually transmitted diseases

The herpes simplex virus (HSV), generally type II, causes this sexually transmitted disease. This condition usually causes outbreaks:

  • Very painful blisters near the infection site.
  • Intense genital itching, especially in the affected areas.
  • Dyspareunia or dysuria, depending on the location of the blisters.

This condition is diagnosed by taking a sample from the sore. No treatment can cure this virus, which is why the carrier will have it for the rest of their lives. However, some medications can help improve symptoms and make them disappear faster.


Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. Just like chlamydia, it doesn’t manifest with characteristic symptoms. So consequently, it may go unnoticed for a long time.

Any of these symptoms can manifest:

  • Dysuria.
  • Increased vaginal discharge.
  • Breakthrough bleeding.
  • Penile discharge.
  • Pelvic inflammatory disease (PID).

It’s diagnosed by endocervical swabs and urethral discharge test. The proper treatment is antibiotics.

Learn All About Sexually Transmitted Diseases


Caused by the bacterium Treponema pallidum, syphilis is a condition with a characteristic clinical presentation that’s classified into several stages according to its evolution:

  • Primary syphilis. A skin lesion known as a chancre appears. It occurs 2 to 6 weeks after infection.
  • Secondary syphilis. It occurs 4 to 10 weeks after infection. The infection spreads through the lymph and blood and systemic symptoms such as syphilitic roseola or mucosal lesions appear.
  • Latent syphilis. If left untreated, it can remain asymptomatic in the carrier.
  • Tertiary syphilis. Months or years after infection occurs. Although the carrier can’t spread the disease, the deterioration is great because it can affect the carrier at a musculoskeletal and cardiovascular level.

Without treatment, syphilis can be fatal. Medical professionals diagnose it by blood tests and culture of the ulcer or chancre. The treatment is based on antibiotics.

More types of sexually transmitted diseases


The protozoa Trichomonas vaginalis causes this sexually transmitted disease. Symptoms appear between 5 and 28 days after infection. Some of them are very characteristic:

  • Frothy yellowish or greenish vaginal discharge.
  • Malodorous vaginal discharge.
  • Dyspareunia.
  • Dysuria.
  • Genital itching.

Medical professionals diagnose it by a vaginal swab or urethral discharge culture. To treat this condition, the carrier must take antibiotics.

Human papillomavirus (HPV)

HPV is a common virus and, depending on the strain, it causes some symptoms or others. There are over 100 different types. Some of the most important are:

  • Low-risk HPV strains (6 and 11) cause genital warts, also called condylomata acuminata.
  • High-risk HPV strains (16 and 18) are responsible for a high percentage of cervical cancers, and also vulvar, vaginal, anal, and penile cancer.

It’s diagnosed by cervical cytology in women, and scrape cytology in men. There’s no treatment to eliminate the virus. However, the body often eliminates it naturally. Lesions may appear, either genital warts or lesions on the cervix; they can be treated.

To prevent infection, there’s a vaccine against human papillomavirus that’s given to girls of a certain age in most regions. Likewise, it can be administered to women in adulthood.

Ask your midwife or gynecologist about this vaccine, as well as any doubts you may have. Also, you should consider getting vaccinated.

Acquired immune deficiency syndrome (AIDS)

The human immunodeficiency virus (HIV) causes this disease. This virus attacks the immune system, weakening it and making the carrier prone to other diseases and infections.

HIV can be transmitted from mother to baby during pregnancy and through exposure to infected body fluids.

Not all people infected with the virus develop acquired immune deficiency syndrome (AIDS). Some of the symptoms it causes include:

  • Early symptoms. Similar to a common cold, swollen glands, general malaise, and weight loss, among others.
  • Severe symptoms don’t manifest until months or years later.

It’s diagnosed by laboratory testing. Today, experts are studying new treatments for this disease. In addition, currently, antiretroviral therapy (ART) can improve the quality of life and life expectancy of affected patients.

Learn All About Sexually Transmitted Diseases

Hepatitis B (HB)

The hepatitis B virus (HBV) can be transmitted through exposure to bodily fluids during sexual intercourse, through contact with blood parenterally, or during pregnancy from mother to baby.

This is a serious infection that affects the liver. The most worrisome fact is that it has no cure. Although it doesn’t have characteristic symptoms, it can cause fatigue, abdominal pain, loss of appetite, and fever, among others. In addition, medical professionals diagnose it with blood tests.

You should know that there’s a vaccine against the hepatitis B virus (HBV). Ask your doctor about it and consider getting the vaccine.

Conclusion on sexually transmitted diseases

If you’ve had risky sex or want to know more about your sexual health or available contraception methods, please consult your midwife or trusted health care professional.

If you’re going to have sex with or without penetration, use a barrier contraceptive method. Protect yourself. And remember: your sexual health is very important and depends on you!

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Andrés Domingo, P. (2017). Infecciones de transmisión sexual. Pediatria Integral.
  • Díez, M., & Díaz, A. (2011). Infecciones de transmisión sexual: epidemiología y control. Revista Española de Sanidad Penitenciaria. https://doi.org/10.4321/s1575-06202011000200005
  • Belda, J., Díaz, A., Ezpeleta, G., Fernández, E., Junquera, M. L., Martínez, B., … Zafra, T. (2011). Infecciones De Transmisión Sexual: Diagnóstico, Tratamiento, Prevención Y Control. Ministerio de Sanidad, Política Social e Igualdad.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.