Sexually Transmitted Infections (STIs)

Sexually transmitted  infections (STIs) primarily attack your sexual and reproductive organs, and can affect other areas of the body as well. STIs are spread during close sexual contact, such as vaginal or anal sexual intercourse and oral sex.

Below are important facts you should know about sexually transmitted infections.

  • STIs are extremely common. Sexually active teens have the highest rates of sexually transmitted infections in the United States.
  • In the US, there are about 10 million new cases of STIs each year in people 15-24 years of age.
  • The most common STIs are trichomoniasis, HPV (genital warts), chlamydia, gonorrhea and herpes. Syphilis and HIV are less common, but still can affect teens.
  • Most teens who have an STI have no symptoms.
  • If you are having any sexual contact, including oral sex, you are at risk for STIs.
  • If you think you might have an STI or had sex with someone who has an STI, see a healthcare provider as soon as possible.
  • Untreated STIs can cause chronic pain and infertility (the inability to have children) in the future and increase your risk of having a life-threatening tubal pregnancy.
  • STIs will not go away without treatment; symptoms may disappear but the damage continues or gets worse.
  • Almost all STIs can be cured. The sooner you get attention, the less chance there is of permanent damage.
  • In all states, teens can be tested or treated for STIs confidentially, that is, without notifying a parent or guardian. Check with your healthcare provider about their policy on confidential services.

If you have been diagnosed with an STI:

  • Tell your sexual partner. Your partner also needs to be treated.
  • Stop all sexual activity until your healthcare provider tells you it is safe.
  • Follow your healthcare provider's instructions. Take all of your medicine.

To prevent STIs you can:

  • Choose not to have oral, vaginal, or anal sex. This is the best way to prevent STIs.
  • Use a condom whenever you have sex. Condoms are not perfect, but will decrease your risk of STIs.
  • Limit your number of sexual partners. Each time you are sexually active with a new partner you may get any infections that they already have (see sex map, below). It is usually not possible to tell if your sexual partner has an STI.

(pronounced Trik-uh-moan-ee-AS-us)
Trichomoniasis [also called trichomonas or trich (pronounced "trik")] is an infection that is caused by a parasite. It is one of the most common STIs in teens and older women.


Fifty percent of women and 90 percent of men with trichomonas may have no symptoms.

Females with trichomonas may have a yellow or greenish vaginal discharge with a strong odor, vaginal irritation and itching. Males may have burning with urination or discharge from the penis.

Diagnosis and Treatment

Trichomonas can be diagnosed by examining vaginal or penile discharge, or by a laboratory test (culture). Both partners take the drug metronidazole to treat the infection.


Trichomonas can persist for a long time. People who are infected with trichomonas are at increased risk of getting other STIs, especially HIV. Pregnant women with trichomonas can have complications.


Ninety-five percent of females with chlamydia do not notice any symptoms. Some females with chlamydia develop symptoms seven to 21 days after having sex. Symptoms include discharge from the vagina; pain and/or burning upon urination; and pain in the lower abdomen sometimes with fever and nausea, and abnormal bleeding or spotting.

Most males with chlamydia do not have any symptoms. Males with chlamydia can experience watery, white drip from the penis, or pain or burning upon urination.

Diagnosis and Treatment

Diagnosis is made by testing the urethral / cervical discharge, or by obtaining a urine sample. Treatment with antibiotics such as azithromycin or doxycycline is the most effective.

If Untreated

If untreated, females can develop pelvic inflammatory disease, an infection of the fallopian tubes, ovaries and pelvic area. Females can have ongoing pelvic pain as a result of chlamydia infections. Sterility can result from scar tissue blocking the tubes.

If untreated in males, pain can develop first in the penis then to other parts of the genitals. In addition, sterility can develop due to damage to the sperm passageway.

Newborns who pass through the birth canal of infected females can experience eye damage or infant pneumonia.

(pronounced Gon-or-EE-uh)


Many females with gonorrhea (also known as "clap," "drip," or "gc") will not notice any symptoms. Some females with gonorrhea will develop symptoms about two to 21 days after having sex.

Symptoms include thick yellow or green discharge from the vagina; burning or pain upon urination; abdominal pain or tenderness; and a menstrual period that is not normal (heavier, irregular time, or more cramping).

Males may experience thick yellow or white drip from the penis, or pain or burning upon urination. They may not experience any symptoms.

Diagnosis and Treatment

Diagnosis is made on the basis of physical exam and laboratory tests on the secretions from the patient's penis, cervix, etc. A urine test can also detect gonorrhea. Treatment with antibiotics includes an injection of Ceftriaxone and a dose of azithromycin by mouth and can cure gonorrhea in most cases safely and effectively. A follow-up exam helps make sure treatment is effective.

If Untreated

Similar to those listed for chlamydia. In addition, gonorrhea can damage joints, and eye and heart tissues.

(pronounced HER-pees)


Symptoms of herpes (also known as "hsv") can occur in males and females within two to 30 days after having sex. Both males and females can experience flu-like symptoms (fever, aches, fatigue). Small, painful blisters on the sex organs (vagina or penis) or the mouth can appear along with itching and burning. Blisters last one to three weeks and then go away; they can come back any time. Herpes is easily spread through oral sex. Many people have herpes without knowing it.

Diagnosis and Treatment

Diagnosis is made by examination of genital sores and laboratory testing. Currently there is no cure for herpes, but with acyclovir the episodes can be prevented or shortened. The use of condoms can decrease transmission. 


Herpes can cause risk of death, brain damage, etc., in babies of infected females; and an increased risk of miscarriage or premature births.

(pronounced Human Pap-uh-LOAM-uh Virus)


Human papillomavirus (also known as "HPV") is the most common STI. Because it is a virus, it is not curable. Most infections clear up on their own, but some can persist. There is a vaccine which lowers the chance of getting HPV. Ask your doctor about it.

The majority of those infected with HPV have no symptoms. Some of those infected with HPV may notice warts on the genital area (penis, vulva). HPV infection can also cause abnormal results on a Pap test. (Women have Pap tests to check for abnormal or precancerous cells on the cervix).

Diagnosis and Treatment

HPV is diagnosed by clinical exam and lab testing. Warts can be removed by freezing, burning or applying chemicals. If abnormal cells are found on the Pap test, these can be treated so that they do not progress into cervical cancer.


Women with HPV are at risk of developing genital warts and cervical cancer. Men with HPV are at risk of developing genital warts and penile cancer. HPV also causes anal, oral and throat cancer in both men and women.

(pronounced sih-fill-us)


Syphilis is divided into three stages, where symptoms in males and females change from stage to stage. Many people with syphilis do not notice symptoms.

First Stage (1-12 weeks after contact)
A reddish ulcer called a chancre (shang-ker) sore appears on the genitals, mouth or anus. It lasts one to five weeks and is painless. Not all people with syphilis develop a chancre; not all who develop a chancre notice it. Many women will not notice a chancre because it is inside the vagina.

Second Stage (1-6 months after contact)
Symptoms may include a rash on the chest, back, arms and legs; enlarged lymph nodes on neck, under arms, in groin, etc.; fever, sore throat and feeling sick all over. Symptoms go away, but sores and rash may appear again.

Third Stage (3 years or more after contact)
Symptoms include ulcers on the skin and internal organs; arthritis; loss of feeling in arms and legs; and pain and disability due to damage to the heart, blood vessels, spinal cord and/or brain (uncommon).

Diagnosis and Treatment

Diagnosis of syphilis includes a physical exam with blood samples or material from sores being examined in the laboratory. Treatment with an antibiotic -- usually penicillin -- cures syphilis. Follow-up is required to assure that treatment has been effective. Treatment cannot cure any permanent damage that has occurred.

If Untreated

If left untreated, syphilis may cause heart damage and damage to major blood vessels, resulting in heart failure and usually death. Another result is brain and spinal cord damage causing paralysis, insanity and eventually death. In addition, birth defects and death can occur to newborns whose mothers have syphilis.

HIV is a sexually transmitted infection that can be acquired by sexual contact, sharing an infected needle or syringe, or exposure to infected body fluids (blood, semen, etc.). The CDC recommends everyone be tested for HIV at least once and regularly if someone is having sex.


Most people who are infected with HIV show no symptoms in the early stages of infection. Symptoms of HIV can show up in males and females several months to several years after contact with the virus. Symptoms include recurrent fever, unexplained weight loss, swollen lymph nodes, fatigue, diarrhea, appetite loss and white spots or unusual blemishes in the mouth. When prolonged infection with HIV progresses, it leads to extensive damage of the body's immune system, and is called AIDS (acquired immune deficiency syndrome).


Presently there is no cure for HIV. Ongoing medical therapy controls the virus and prolongs the life expectancy of those infected. The infection can be prevented by avoiding intravenous drug use and sex with anyone who is infected with HIV or at risk of infection with HIV. Thus, preventing other STIs will decrease your chance of getting HIV.


Jane and John have had sexual intercourse together for the first time. They don't think they could have an STI, because they have never been promiscuous. 

Jane thinks she has been exposed to two partners in her lifetime: John and Ben, with whom she had sex three months ago.  

John thinks he has been exposed to three partners: Jane, Sue (three months ago), and Theresa (last year).  

Ben, Sue and Theresa each had previous sex with two other partners. Therefore, Jane and John each have been exposed to 10 partners. Jane doesn't know anything about eight of those partners, and John doesn't know anything about seven of them. If any one of the people on this map has an STI, Jane or John can now have it also. 

Last Updated 10/2014