Sexually transmitted diseases (STDs)

Sexually transmitted diseases (STDs), or sexually transmitted infections (STIs), are generally acquired by sexual contact. The organisms that cause sexually transmitted diseases may pass from person to person in blood, semen, or vaginal and other bodily fluids.

Some such infections can also be transmitted nonsexually, such as from mother to infant during pregnancy or childbirth, or through blood transfusions or shared needles.

It's possible to contract sexually transmitted diseases from people who seem perfectly healthy — people who, in fact, aren't even aware of being infected. Many STDs cause no symptoms in some people, which is one of the reasons experts prefer the term "sexually transmitted infections" to "sexually transmitted diseases."

Symptoms Causes Risk factors Complications Prevention

Sexually transmitted infections (STIs) have a range of signs and symptoms. That's why they may go unnoticed until complications occur or a partner is diagnosed. Signs and symptoms that might indicate an STI include:

  • Sores or bumps on the genitals or in the oral or rectal area
  • Painful or burning urination
  • Discharge from the penis
  • Unusual or odd-smelling vaginal discharge
  • Unusual vaginal bleeding
  • Pain during sex
  • Sore, swollen lymph nodes, particularly in the groin but sometimes more widespread
  • Lower abdominal pain
  • Rash over the trunk, hands or feet

Signs and symptoms may appear a few days to years after exposure, depending on the organism.

When to see a doctor

See a doctor immediately if:

  • You are sexually active and you believe you've been exposed to an STI
  • You have signs and symptoms of an STI

Make an appointment with a doctor:

  • When you consider becoming sexually active or when you're 21 — whichever comes first
  • Before you start having sex with a new partner

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