Sexually Transmitted Diseases (STDs)

Reviewed on 10/13/2021

Sexually Transmitted Diseases (STDs) Definition and Facts

Man and woman holding each other.
STDs in the US are at an all-time high.

Sexually transmitted diseases (STDs, venereal diseases) are among the most common infectious diseases in the United States today. STDs are sometimes referred to as sexually transmitted infections since these conditions involve the transmission of an infectious organism between sex partners. More than 20 different STDs have been identified, and about 19 million men and women are infected each year in the United States, according to the CDC (2010).

Depending on the disease, the infection can be spread through any type of sexual activity involving the sex organs, the anus, or the mouth; an infection can also be spread through contact with blood during sexual activity. STDs are infrequently transmitted by other types of contact (blood, body fluids, or tissue removed from an STD infected person and placed in contact with an uninfected person). However, people that share unsterilized needles markedly increase the chance to pass many diseases, including STDs (especially hepatitis B), to others. Some diseases are not considered to be officially an STD (for example, hepatitis types A, C, E) but are infrequently noted to be transferred during sexual activity. Consequently, some authors include them as STDs, while others do not. Some lists of STDs can vary, depending on whether the STD is usually transmitted by sexual contact or only infrequently transmitted.

  • STDs affect men and women of all ages and backgrounds, including children. Many states require that Child Protective Services be notified if children are diagnosed with an STD.
  • STDs have become more common in recent years, partly because people are becoming sexually active at a younger age, are having multiple partners, and do not use preventive methods to lessen their chance of acquiring an STD. Seniors show a marked increase in STDs in the last few years as many do not use condoms.
  • People can pass STDs to sexual partners even if they do not have any symptoms.
  • Frequently, STDs can be present but cause no symptoms, especially in women (for example, chlamydia, genital herpes, or gonorrhea). This can also occur in some men.
  • Health problems and long-term consequences from STDs tend to be more severe for women than for men. Some STDs can cause pelvic infections such as pelvic inflammatory disease (PID), which may cause a tubo-ovarian abscess. The abscess, in turn, may lead to scarring of the reproductive organs, which can result in an ectopic pregnancy (a pregnancy outside the uterus), infertility, or even death for a woman.
  • Human papillomavirus infection (HPV infection), an STD, is a known cause of cancer of the cervix.
  • Many STDs can be passed from a mother to her baby before, during, or immediately after birth.
  • Because the method of becoming infected is similar to all STDs, a person often obtains more than one pathogenic organism at a time. For example, many people (about 50%) are infected at a single sexual contact with both gonorrhea and chlamydia.

What Are the Symptoms and Signs of Sexually Transmitted Diseases?

Common STDs have a variety of symptoms (if symptoms develop at all) and many different complications, including death.

Symptoms of STDs caused by bacteria

Chancroid Symptoms

  • Are not common in the United States but common in developing countries.
  • Symptoms include painful ulcers on the genitals.
  • Can be confused with syphilis or herpes
  • Is treatable with antibiotics

Chlamydia symptoms

  • The most common of all STDs are caused by bacteria.
  • Cause no symptoms in about 80% of women and 50% of men
  • When symptoms are present, commonly there is discharge from the vagina or the penis, and burning or pain during urination.
  • Is transmitted through vaginal, oral, or anal sexual contact
  • Ectopic pregnancy and infertility for women are potentially serious complications.
  • Is treatable with antibiotics

Gonorrhea symptoms

  • Discharge from the vagina or the penis
  • Over 50% of infected women have no symptoms, but they can still transmit the disease to others.
  • Painful urination
  • Ectopic pregnancy, pelvic inflammatory disease (PID), infertility for women, Fitzhugh-Curtis syndrome (perihepatitis), and death are potentially serious complications.
  • Is treatable with antibiotics, but many strains are becoming resistant to most antibiotics.

Granuloma inguinale (donovanosis) symptoms

  • Not common in the U.S.
  • Symptoms are painless genital ulcers in the groin area.
  • Is treatable with antibiotics, usually for three or more weeks

Lymphogranuloma venereum symptoms

  • Not common in the U.S.
  • Symptoms are abscesses (buboes) in the groin, rectum, or other areas; fistulas that drain pus may occur and are treatable with antibiotics.
  • This disease is treated with antibiotics.

Syphilis symptoms

  • Symptoms are mild and often go undetected initially
  • Starts with a painless genital ulcer that goes away on its own
  • Rash, fever, headache, achy joints
  • Is treatable with antibiotics
  • More serious complications associated with later stages of the disease if undetected and untreated

Symptoms of STDs caused by viruses

Genital herpes

  • Recurring outbreaks of blister-like sores on the genitals
  • Can be transmitted from a mother to her baby during birth
  • Reduction in frequency and severity of blister outbreaks with treatment but not complete elimination of infection.
  • Can be transmitted by a partner who has herpes even if no blisters are present.

Genital warts

  • Caused by a virus related to skin warts, human papillomavirus (HPV)
  • Small, painless bumps in the genital or anal areas (sometimes in large clusters that look like cauliflower)
  • Various treatments available (for example, freezing or painting warts with medication)
  • Vaccines are available against the most common types of HPV


  • Hepatitis B and D are most often associated with sexual contact, hepatitis A, C, E are less frequently transmitted by sexual contact.
  • Both may be transmitted via contact with blood; for hepatitis B, sexual transmission is believed to be responsible for 30% of the cases worldwide.
  • The hepatitis B virus can cause both an initial (acute) and a chronic form of liver inflammation. Only 50% of acute infections with the hepatitis B virus produce symptoms. The initial phase of infection lasts a few weeks, and in most people (90% to 95%), the infection clears.
  • Acute infection can cause yellowish skin and eyes, fever, achy, tired (flu-like symptoms).
  • Severe complications in some people, including cirrhosis and liver cancer may occur in a small percent of individuals infected with HBV.
  • Treatments are available and remission is possible with some aggressive medications.
  • Immunizations are available to prevent hepatitis B.


  • Spread primarily by sexual contact and from sharing IV needles
  • Can be transmitted at the time a person becomes infected with other STDs
  • No specific symptoms or physical signs confirm HIV infection.
  • The average time from infection to the development of symptoms related to immunosuppression (decreased functioning of the immune system) is 10 years.
  • The following symptoms may occur a few weeks after contracting the virus initially (acute retroviral syndrome, acute HIV infection):
  • Serious complications of AIDS include
    • unusual infections or cancers,
    • weight loss,
    • intellectual deterioration (dementia), and
    • death.
  • No current cure but medications are available to slow disease progression and make it a chronic, manageable disease.

Molluscum contagiosum

  • Small (2 to 5mm) raised areas (papules) on the skin
  • Contagious, usually by direct skin to skin contact
  • Self-limited over months to years; treated with some topical creams
  • Often cryotherapy (freezing) or surgical removal is performed

What Are Other Symptoms and Signs STDs?

Symptoms of STDs caused by protozoan


  • Frothy vaginal discharge with a strong odor
  • Treated with antibacterial/antiprotozoal medicines

Symptoms of STDs* caused by fungi*

Jock itch (genital itching or Tenia cruris)* (not always an STD)

  • Itchy groin skin, sometimes has a reddish color
  • Is treated with topical antifungal medicines

Yeast infection (Candidiasis)* (not always an STD)

  • Cheese-like vaginal discharge or whitish exudates sometimes with a reddish hue to the skin; it may occur around the foreskin of infected males; common symptoms are itching and burning sensation of the vagina or penis.
  • Is treated either with topical or oral antifungal medicines.

Symptoms of STDs caused by parasites

Pubic lice

  • Very tiny bugs that are found in pubic hair, sometimes referred to as "crabs"
  • Can be picked up from clothing or bedding
  • First noticed as itching in the pubic area
  • Are treatable with creams, anti-lice agents, and combing


  • Skin infestation caused by a tiny mite
  • Highly contagious
  • Intense itching is the primary symptom, which worsens at night
  • Spread primarily by sexual contact or from contact with skin, infested sheets, towels, or furniture
  • Is treated with creams

What Are the Types and Causes of Sexually Transmitted Diseases?

Depending on the disease, STDs can be spread with any type of sexual activity. STDs are most often caused by viruses and bacteria. The following is a list of the most common STDs, their causes. Additionally, there are other infections (see STDs with asterisk mark*) that may be transmitted on occasion by sexual activity, but these are typically not considered to be STDs by many investigators:

STDs caused by bacteria

  • Chancroid (Haemophilus ducreyi)
  • Chlamydia (Chlamydia trachomatis)
  • Gonorrhea (Neisseria gonorrhea)
  • Granuloma inguinale (Calymmatobacterium granulomatis)
  • Lymphogranuloma venereum (Chlamydia trachomatis)
  • Syphilis (Treponema pallidum)

STDs caused by viruses

STD caused by protozoan

STD's* caused by fungi

  • Jock itch (Tenia cruris)*
  • Yeast infections* (Candida albicans)

STD's caused by parasites

For details about the pathogens that cause the diseases, the reader is urged to search the specific disease by simply clicking on it.

When Should You Call a Doctor about STDs?

A medical examination may be necessary if a person believes he or she may have an STD or if he or she may have been exposed to someone with an STD. Being seen by a doctor as soon as possible after exposure to an STD is important; these infections can easily spread to others and can have serious complications.

Go to your primary care physician or an urgent care center or STD clinic in these circumstances if:

  • an STD problem worsens or
  • a fever develops with other symptoms.

What Tests Diagnose Sexually Transmitted Diseases (STDs)?

Some STDs can be diagnosed without any tests at all (for example, pubic lice). Other STDs require a blood test or a sample of any unusual fluid (such as an abnormal discharge from the vagina or the penis for gonorrhea or chlamydia) to be analyzed in a lab to help establish a diagnosis. Some tests are completed while a person waits; other tests require a few days before a person may obtain the results (for example, syphilis).

What Home Remedies Soothe Symptoms of Sexually Transmitted Diseases?

Home treatment of STDs is not recommended because prescription medications are usually necessary.

What Is the Treatment and Cure for STDs?

The treatment of an STD varies depending on the type of STD. Some STDs require a person to take antibiotic medication either by mouth or by injection; other STDs require a person to apply creams or special solutions on the skin. Often, reexamination by a doctor is necessary after the treatment to confirm that the STD is completely gone.

Some STDs, such as genital herpes and HIV (which leads to AIDS), cannot be cured, only controlled with medication.

For treatment of individual STD types, the reader is urged to click on the individual disease listed above.

How Do You to Seek Help for Sexually Transmitted Diseases (STDs)?

Sometimes people with STDs are too embarrassed or frightened to ask for help or information. However, most STDs are easy to treat. The sooner a person seeks treatment and warns sexual partners about the disease, the less likely the disease will do permanent damage, be spread to others, or be passed to a baby.

If diagnosed with an STD, follow these guidelines:

  • Seek treatment to stop the spread of the disease.
  • Notify sexual contacts and urge them to have a checkup.
  • Take all of the prescribed medication, even if symptoms stop before all of the prescribed medication(s) are taken.
  • Sometimes, follow-up tests are important to comply with the instructions given by the health care practitioner.
  • Consult a doctor with specific needs and any questions about reinfection, sexual partner notification, and prevention.
  • Avoid sexual activity while being treated for an STD.

What Is the Prognosis for Sexually Transmitted Diseases (STDs)? Are They Fatal?

Most of the common STDs can be cured with treatment.

  • In addition to the discomfort of the infection, some STDs can cause other, more serious, long-term problems, including infertility and problems in newborns infected by their mothers during pregnancy such as blindness, bone deformities, developmental disabilities, and infrequently, death.
  • HIV can only be slowed, not eliminated, and may cause death.

How Can You Prevent Sexually Transmitted Diseases (STDs)?

The best way to prevent STDs is to avoid sexual contact with others. If people decide to become sexually active, they can reduce the risk of developing an STD in these ways:

  • Practice abstinence (refrain from sex entirely) or be in a monogamous relationship (both sexual partners are each other's, only sexual partner).
  • Delay having sexual relations as long as possible. The younger people are when they become sexually active, the higher the lifetime risk for contracting an STD. The risk also increases with the number of sexual partners.
  • Correctly and consistently use a male latex condom. The spermicide nonoxynol-9, once thought to protect against STDs as well as to prevent pregnancy, has been proven to be ineffective for disease prevention. Do not rely on it. In addition, condoms are only about 90% effective in preventing STDs
  • Have regular medical checkups even if you do not have symptoms of an STD.
  • Learn the symptoms of STDs.
  • Avoid douching because it removes some of the natural protection in the vagina.
  • Vaccines against HPV and hepatitis B are available and effective.

What Are the Early Symptoms and Signs of STDs in Men?

STD symptoms and signs depend on the type of infection, for example:

  • Severe bouts of painful blisters on the penis
  • Urethritis
  • Throat or rectum infection
  • Diarrhea
  • Anal discharge or drainage
  • Inflammation of the testicle
  • Painful lymph nodes
  • Vomiting
  • Joint pains
Reviewed on 10/13/2021
April is STD Awareness Month. CDC.