Sexually transmitted infections (STIs) or sexually transmitted diseases, as they used to be called, spread from one person to another during sexual contact. This contact can involve the genitals, anus, skin, or mouth and result in an infection.


There are more than 20 types of STIs. The most common STIs are herpes simplex virus (HSV), genital warts, molluscum contagiosum, pubic lice (crabs), scabies, chlamydia, gonorrhea, syphilis, hepatitis B and C, and HIV/AIDS.

Herpes simplex virus-1

Herpes simplex virus-1

Herpes simplex virus

Herpes simplex causes painful sores in or around the genitals and/or mouth. Sores can go away and not return for many years. The disease spreads from one person to another through close physical contact. Sometimes sharing objects that touched open sores can spread the virus.

There are two types of herpes simplex virus: HSV-1 and HSV-2. HSV-1 often causes sores around the mouth, which many refer to as cold sores or fever sores. HSV-2 is more often the cause of genital herpes. Sometimes HSV-1 causes genital sores.

It is possible to spread the virus when there are not visible sores or symptoms. A mother with genital herpes can infect her newborn during childbirth. Appropriate precautions must be taken at the time of the delivery.

There is no cure for either types of HSV, but treatment can make HSV outbreaks shorter and milder. Long-term treatment may decrease the chance of spreading the virus when there are no symptoms.

Genital warts

Genital warts are caused by some types of the human papillomavirus (HPV). HPV can cause cauliflower-shaped growths or pink or brown bumps to appear in the genital region. These warts can grow in size and number. HPV spreads through genital contact with an infected person.

It can be hard to get rid of genital warts. You may need many visits to the dermatologist. Treatments include freezing, burning, topical therapies, and surgically removing the warts.

Genital warts

Genital warts

Some HPV types can cause cancer of the cervix in women. Women can get an HPV test with their Pap test.

There are two vaccines (shots) that can prevent HPV infection that causes cervical cancer. To get the most protection from these vaccines, you should get vaccinated before you become sexually active.

Molluscum contagiosum

Molluscum contagiosum is a common skin disease, caused by a virus that spreads easily between people. Molluscum is usually harmless. This STI causes small, shiny bumps on the skin. The virus that causes the bumps spreads by skin-to- skin contact. You can get the virus without having sex.

Children are more likely than adults to get molluscum. This is because they naturally have more skin-to-skin contact with others.

In a healthy person the bumps may go away on their own. Treatment can help get rid of the bumps more quickly. There

are a few effective treatments. These include curettage (scraping), cryosurgery (freezing), and medicines applied to the skin.

Molluscum contagiosum

Molluscum contagiosum

Pubic lice (crabs)

Pubic lice are tiny insects that lay their eggs in the person’s pubic hair, causing an infestation. The infested area often itches. People can get pubic lice from having sex with an infected person or using infected bedding, towels or clothes. The infestation continues until the person receives medicine to kill the lice. You also must find the source of the lice and avoid further contact.

Pubic lice

Pubic lice


Scabies is another common skin condition. People get scabies when the scabies mite burrows into the top layer of their skin. When the person’s skin reacts to the mite, a very itchy rash develops.

People often get the mites on their skin through skin-to-skin contact. The longer the skin-to-skin contact, the more likely you are to get mites on your skin. Adults may get scabies through sexual contact. It is also possible to pick up the mites by sharing a towel, bedding or clothing with a person who has scabies.

Medicine is needed to treat scabies. Proper cleaning of contaminated cloths is important, too. Cleaning removes the mites and prevents reinfection. Most often, if someone in a family is diagnosed with scabies, everyone living in the household needs treatment.

Chlamydia and Gonorrhea

Chlamydia and gonorrhea spread through sexual contact with an infected person. Both can cause a whitish discharge from the vagina or penis, and burning while urinating. Some people do not have symptoms. This makes chlamydia and gonorrhea hard to detect. Without treatment, the infection may lead to pelvic inflammatory disease in women. This disease can prevent women from having children.

For these reasons, early diagnosis and treatment are important. Antibiotics can cure chlamydia and gonorrhea. Sexual partners should also be treated.




Syphilis causes sores on the body, most often around the genitals and mouth. The sores are usually not painful. A rash can follow after the sores go away if the person does not get treatment. Without treatment, syphilis can damage the heart, blood vessels, brain, and nervous system. People get syphilis through sex and by touching the sores. A baby can become infected during birth.

Doctors use a blood test to find syphilis. Antibiotics can cure syphilis. Sexual partners must get treatment as well.

Hepatitis B and C

Both hepatitis B and C can be spread through sex. Hepatitis B can cause fever, muscle aches, vomiting, diarrhea, and liver damage. The hallmark of hepatitis C is yellow skin (jaundice). Hepatitis C is the most common cause of long-lasting liver disease. It may require a liver transplant.

A blood test can detect hepatitis B. There is a vaccine to prevent hepatitis B, which requires three shots. There is no vaccine to prevent hepatitis C.


The human immunodeficiency virus (HIV) suppresses the immune system. This can result in long-lasting infections, diarrhea, fever, and weight loss. If the infection progresses to AIDS, it can be fatal. Besides spreading through sex, HIV can spread from sharing needles.

Treatments can slow progression of the disease. There is no cure or vaccine to prevent HIV.


Most of the time you cannot tell if someone has an STI. Many people get an STI from someone who has no symptoms.

People may not know they have an STI or may not tell you if they do know. If you have sexual contact even once with an infected person, you can get an STI.


Some STIs can be passed by a mother to her baby during childbirth. STIs that can be passed include herpes simplex, genital warts, chlamydia, gonorrhea, syphilis, and HIV. If you are pregnant and have any of these STIs, ask your doctor what precautions you need to take.


To protect yourself from STIs:

  • Have as few sexual partners in your lifetime as possible. This reduces your risk. Some STIs are so common that

avoiding all sexual activity – genital, anal or oral – is the only method that is 100% effective.

  • Use condoms. Latex condoms, when used properly, can lessen the risk of getting infected with STIs that spread by body fluids. It is important to know that condoms do not offer complete protection against STIs such as herpes, genital warts, syphilis, molluscum contagiosum, pubic lice, and scabies. These all can spread by
  • Know that birth control pills do NOT protect against STIs. Birth control pills only protect against

A board-certified dermatologist is a medical doctor who specializes in diagnosing and treating the medical, surgical, and cosmetic conditions of the skin, hair and nails. To learn more or find a dermatologist in your area, visit or call toll free (888) 462-DERM (3376).

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