ConditionInfections
Sexually Transmitted Diseases (STDs)
Sexually transmitted diseases (STDs), also called sexually transmitted infections (STIs), are infections passed through vaginal, anal or oral sex and sometimes skin-to-skin genital contact. The most common are chlamydia, gonorrhea, syphilis, trichomoniasis, genital herpes, HPV and HIV. Many cause no symptoms, so testing is the only way to know. Bacterial and parasitic STDs are curable with antibiotics; viral ones are controllable. Condoms, vaccines and regular testing prevent most infections.
Also called: STD, STI, sexually transmitted infection, venereal disease (older term)
At a glance
- What they are
- Infections spread through sexual contact.
- Bacterial (curable)
- Chlamydia, gonorrhea, syphilis, plus parasitic trichomoniasis.
- Viral (manageable)
- Herpes, HPV, HIV, hepatitis B.
- Symptoms
- Often none; discharge, burning urination, sores, rashes, pelvic pain, warts.
- Testing
- Urine tests, swabs and blood tests; often free or low-cost.
- Prevention
- Condoms, HPV and hepatitis B vaccines, PrEP for HIV, partner testing.
When to get help
Call 911 or go to the ER
- Severe lower belly pain with fever, vomiting or fainting in someone who could have pelvic infection or ectopic pregnancy
- Sudden severe testicle pain and swelling (rule out testicular torsion)
See a doctor within a day or two
- A possible HIV exposure in the last 72 hours, such as condomless sex with a partner who has HIV or unknown status, or sexual assault (HIV PEP must start within 72 hours)
- Pelvic pain, pain during sex or fever with abnormal discharge (possible pelvic inflammatory disease)
- Painful, swollen testicle or scrotum with discharge
- A rash on the palms and soles, or headache, vision or hearing changes with a recent sore (possible syphilis)
- A sexual partner diagnosed with an STD
Book a routine appointment
- Unusual discharge, burning when urinating, sores, bumps, blisters or warts on the genitals or mouth
- Bleeding between periods or after sex
- New sexual partner or multiple partners: routine testing
- Pregnancy: STD testing is part of prenatal care
Usually safe to manage at home
- Mild irritation or small scrapes after sex or shaving that heal within a few days, with no sores, discharge or new partner (test if any doubt)
Common STDs at a glance
| Infection | Type | Common symptoms | Treatment |
|---|---|---|---|
| Chlamydia | Bacterial | Often none; discharge, burning urination, pelvic pain | Antibiotics (doxycycline) |
| Gonorrhea | Bacterial | Discharge, burning, sore throat, rectal pain; often none in women | Antibiotic injection (ceftriaxone) |
| Syphilis | Bacterial | Painless sore, then rash on palms and soles; later organ damage | Penicillin |
| Trichomoniasis | Parasite | Frothy, smelly discharge, itching | Metronidazole |
| Genital herpes | Virus (HSV) | Painful blisters and sores, recurring | Antivirals control outbreaks |
| HPV | Virus | Genital warts; most infections silent; cervical and other cancers | Vaccine prevents; warts and precancer treated |
| HIV | Virus | Flu-like illness early, then often none for years | Lifelong antiretroviral therapy |
| Hepatitis B | Virus | Often none; jaundice, fatigue | Vaccine prevents; antivirals for chronic |
| Mycoplasma genitalium | Bacterial | Urethritis, cervicitis | Specific antibiotics |
Symptoms
Many STDs cause no symptoms, especially chlamydia and gonorrhea in women, and HPV and herpes in many people.
In men
- discharge from the penis
- burning or pain when urinating
- sores, blisters, bumps or warts on the penis, scrotum or anus
- pain or swelling in the testicles
- rectal pain, discharge or bleeding
In women
- unusual vaginal discharge or odor
- burning when urinating
- bleeding between periods or after sex
- pelvic pain or pain during sex
- sores, blisters, bumps or warts on the vulva, vagina or anus
- itching
In anyone
- sore throat after oral sex
- rash, including on the palms and soles (syphilis)
- swollen lymph nodes in the groin
- flu-like symptoms (early HIV)
Who should get tested and when
CDC and USPSTF recommendations include:
- all adults and adolescents aged 13 to 64: HIV test at least once
- all adults: hepatitis C test at least once; hepatitis B test at least once
- sexually active women under 25: yearly chlamydia and gonorrhea testing; older women with risk factors
- pregnant people: syphilis, HIV and hepatitis B, plus chlamydia and gonorrhea if at risk
- men who have sex with men: at least yearly syphilis, chlamydia, gonorrhea and HIV testing, and every 3 to 6 months if at higher risk
- anyone with a new partner, multiple partners or a partner with an STD
Testing usually involves a urine sample, self-collected swabs (vaginal, throat, rectal) and blood tests. Many clinics, health departments and home kits offer confidential testing.
Treatment
- Bacterial and parasitic STDs are cured with antibiotics or antiparasitic medicine. Avoid sex for 7 days after treatment and until partners are treated. Retest in about 3 months, because reinfection is common.
- Expedited partner therapy: in many states, your clinician can give medicine for your partner without a separate visit.
- Herpes: antivirals shorten outbreaks and daily suppressive therapy reduces outbreaks and transmission.
- HPV: warts can be removed; cervical screening catches precancerous changes early.
- HIV: antiretroviral therapy keeps the virus undetectable. Undetectable means untransmittable (U=U).
- Hepatitis B: antivirals for chronic infection when indicated.
Complications of untreated STDs
- pelvic inflammatory disease, infertility, ectopic pregnancy and chronic pelvic pain
- epididymitis in men
- infection passed to babies during pregnancy or birth
- increased risk of HIV transmission
- cervical, anal, throat and penile cancers (HPV)
- neurological, eye and heart damage (syphilis)
- liver cirrhosis and cancer (hepatitis B)
Prevention
- Condoms used correctly every time for vaginal, anal and oral sex; dental dams for oral sex
- Vaccines: HPV (routinely at 11 to 12, recommended through age 26, and an option for some adults to 45), hepatitis B, hepatitis A
- HIV PrEP: daily pills or long-acting injections for people at higher risk
- HIV PEP: within 72 hours of possible exposure
- Doxy-PEP: doxycycline taken after sex is recommended by the CDC for some men who have sex with men and transgender women with a recent bacterial STI
- Regular testing and talking openly with partners
- Limiting the number of partners and mutual monogamy with a tested partner
Frequently asked questions
What are the most common STDs?
The most common in the US are HPV, chlamydia, trichomoniasis, gonorrhea, genital herpes and syphilis. HPV is so common that most sexually active people get it at some point, though most infections clear on their own.
Can you have an STD without symptoms?
Yes. Many STDs, including chlamydia, gonorrhea, HPV, herpes, HIV and early syphilis, often cause no symptoms. You can still pass them on and develop complications, which is why regular testing is recommended for sexually active people.
Can small abrasions on the penis cause bumps and inflammation without an STI?
Yes. Friction from sex or masturbation, shaving, tight clothing, soaps, condoms or lubricants can cause redness, small bumps or irritation that heal within a few days. Balanitis and ingrown hairs are other non-STD causes. Persistent sores, blisters, discharge or bumps should be tested.
How long after exposure should I get tested for STDs?
Chlamydia and gonorrhea can usually be detected about 1 to 2 weeks after exposure. Syphilis blood tests may take 3 to 6 weeks, and modern HIV tests about 2 to 6 weeks. If you have symptoms, test right away. Seek HIV PEP within 72 hours of a high-risk exposure.
Are STDs curable?
Chlamydia, gonorrhea, syphilis and trichomoniasis are curable with the right medicines. Herpes, HIV and hepatitis B cannot usually be cured but are effectively controlled with treatment. HPV often clears on its own, and its effects can be treated.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Sexually transmitted infections treatment guidelines
- CDC: STI screening recommendations
- US Preventive Services Task Force: Screening for chlamydia and gonorrhea; syphilis; HIV
- World Health Organization: Sexually transmitted infections fact sheet
- MedlinePlus: Sexually transmitted infections