Sexually transmitted diseases

Overview

Sexually transmitted diseases (STDs) are caused by sexually transmitted infections (STIs). They are spread mainly by sexual contact. STIs are caused by bacteria, viruses or parasites. A sexually transmitted infection may pass from person to person in blood, semen, or vaginal and other bodily fluids.

Sometimes sexually transmitted infections are spread in ways other than sexual contact. For example, STIs can spread to infants during pregnancy or childbirth. STIs also can spread through blood transfusions or shared needles.

STIs don't always cause symptoms. A person can get sexually transmitted infections from another person who seems healthy and may not even know they have an infection.

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Symptoms

STDs can have a range of symptoms, including no symptoms. That's why sexually transmitted infections may go unnoticed until a person has complications or a partner is diagnosed.

STI symptoms might include:

• Sores or bumps on the genitals or in the oral or rectal area.

• Painful or burning urination.

• Discharge from the penis.

• Unusual or odorous vaginal discharge.

• Unusual vaginal bleeding.

• Pain during sex.

• Sore, swollen lymph nodes, particularly in the groin but sometimes more widespread.

• Lower abdominal pain.

• Fever.

• Rash over the trunk, hands or feet.

Sexually transmitted infection symptoms may appear a few days after exposure. But it may take years before you have any noticeable problems, depending on what's causing the STI.

When to see a doctor

See a health care professional immediately if:

• You are sexually active and may have been exposed to a sexually transmitted infection.

• You have symptoms of a sexually transmitted infection.

Make an appointment with a health care professional:

• When you're considering becoming sexually active or by age 21, whichever comes first.

• Before you start having sex with a new partner.