Appointment Office - Available only within Brazilian territory. Local call rates apply

7 Most Common STI's, Symptoms & How to Treat

Updated in January 2023

Sexually-transmitted infections like gonorrhea or AIDS are spread through unprotected sexual contact (vaginal, anal or oral). It can affect both men and women of all ages.  

Generally, these infections cause symptoms that affect the genital organs. Symptoms can include pain, redness, small wounds, discharge, difficulty urinating or pain during sex. To identify the STI causing the symptoms, you should see your doctor for testing. 

Chances of getting a sexually-transmitted infection (STI) are higher when a condom is not used, when you have multiple sexual partners or from a one-night stand. 

Imagem ilustrativa número 2

Which STIs are most common?

STIs that are commonly diagnosed include:

1. Chlamydia

Many people with chlamydia do not experience any symptoms and will have chlamydia without knowing, which unfortunately contributes to its spread. The condition is caused by a bacteria and can be spread through unprotected sex or through sharing of sex toys.

Symptoms: Thick and yellow discharge, genital redness, pelvic pain, and pain during sex. 

How to treat: Chlamydia is normally treated with antibiotics like azithromycin or doxycyclin. 

2. Gonorrhea

Gonorrhea is an illness caused by bacteria that can occur in both men or women. It is transmitted through unprotected sex or through sharing of sex toys. 

Symptoms: Pain with urination, yellow discharge similar to pus, vaginal bleeding (outside of a period), abdominal pain, small bumps in the mouth, or pain during sex. 

How to treat: Treatment should be done with ceftriaxone or azithromycin as prescribed by a doctor. If left untreated, gonorrhea can affect the joints and blood and can develop into a life-threatening condition. 

3. Genital warts

Genital warts are associated with the presence of HPV, or human papilloma virus that leads to the growth of skin lesions or warts in the genital area. They can have a smooth or rough consistency and their coloration will vary with skin color. These warts are typically not painful or contagious. he growth of skin lesions, or warts, on genital organs

Symptoms: Skin growths or warts, that may itch, burn or peel. 

How to treat: Genital warts do not have a cure, as the HPV virus remains dormant within the body. However, you can apply topical ointments on the warts. Flare-ups of warts can occur with excessive alcohol consumption, increased fatigue and stress. Read more about how HPV is transmitted and treated. 

4. Genital herpes

Genital herpes is an easily transmitted STI that is spread through the herpes virus. It causes clusters of small red bumps, each containing yellow fluid with the virus. These clusters are usually found on the thighs, anus and sexual organs.

Symptoms: Genital bumps, pain with urination, and discharge in women. 

How to treat: Treatment should be completed with antivirals like acyclovir, valcyclovir or famcyclovir. These help to reduce discomfort associated with symptoms. This infection does not have a cure and symptoms can last for up to 20 days. 

5. Trichomoniasis

Trichomoniasis is a parasitic infection that is not very common, It can be transmitted through sharing moist towels, through bathtubs or through sharing hot tubs.

Symptoms: Gray or yellow-green, foamy discharge with a strong, foul odor. It can also cause redness, intense itching and swelling of sexual organs. 

How to treat: Generally, treatment for this infection is done through metronidazole or tioconazole, taken for 5 to 7 days. If left untreated, trichomoniasis can develop into other infections, trigger premature labor or lead to prostatitis. 

6. Syphilis

Syphilis is an illness that can additionally also be transmitted through a contaminated blood infusion or sharing of needles. The first symptoms usually emerge 3 to 12 weeks after initial contact. Learn more about the phases and symptoms of syphilis.

Symptoms: Dry and painless wounds or red rashes on the hands and feet; this condition can eventually lead to blindness, paralysis and cardiac problems.

How to treat: Treatment is done with medication like penicillin or arithromycin. When taken correctly, there are greater chances for a cure. 


AIDS this illness does not have a cure, therefore treatment is aimed at reducing symptoms and improving quality and quantity of life.

Symptoms:  Fever, sweats, headache, light sensitivity, sore throat, vomiting and diarrhea. Read more about the symptoms of AIDS

How to treat: Treatment is done with antiretrovirals, like zidovudine or lamivudine. These medications help to reduce virus replication rate and strengthen the immune system, however they do not cure this illness. 

How to know if you have an STI 

Diagnosis of a sexually-transmitted infection can be confirmed through assessing the symptoms, inspecting the genital organs and evaluating test results. Common results are a pap test and genital swab. The doctor may also order a blood test to verify the cause for the infection and will indicate the best treatment. 

When to repeat testing

When an STI is contracted, the doctor can order testing every 6 months for the next 2 years, until 3 consecutive tests show negative results. 

During the treatment phase, it may be necessary to see your doctor several times per month to adjust treatment and cure the infection as necessary. 

How STIs can spread 

In addition to unprotected sex, STIs can also be spread in the following ways: 

  • Via blood from mother to baby, during pregnancy, breastfeeding or labor 
  • Sharing needles 
  • Sharing personal items, like towels

In some rare cases, an STI can be transmitted through a blood transfusion. 

How to prevent an STI

The best way to prevent an STI is to use a condom for all sexual activity (vaginal, anal and oral). Contact with secretions or with skin can transmit certain infections. It is important to place the condom correctly to ensure optimal protection.