Sexually Transmitted Infections

What is Sexually Transmitted Infections?

Sexually transmitted infections (STIs), which were formerly known as sexually transmitted diseases, are passed from one person to another through various types of sexual contact, such as oral, anal, or vaginal. STIs can be a problem for healthcare systems, since many of these infections aren’t treated, leading to potentially severe health complications. This article covers the natural course, spread patterns, prevention, examination, diagnosis, and treatments for the most common sexually transmitted infections.

What Causes Sexually Transmitted Infections?

Sexually transmitted infections (STIs) are a major health issue globally and are often overlooked, especially in underprivileged communities. The type of STI a person might get and its symptoms depend on the specific organism, how it’s transmitted, and the person’s individual signs and symptoms. People at higher risk of getting an STI are those who have unprotected sex with multiple partners, have a history of STIs, have experienced sexual assault, engage in prostitution, or have a partner with another sexual partner or history of an STI. They are also more likely if someone regularly consumes alcohol or uses recreational drugs.

An interesting fact is that male circumcision can reduce the chance of getting certain STIs, such as the human papillomavirus, genital herpes and especially HIV, by 50% to 60%. There are seven common STIs. Five of these, chlamydia, gonorrhea, syphilis, and trichomonas, can be completely cured if treated. Herpes simplex virus, HIV, and human papillomavirus (HPV) can’t be cured but can be managed with treatment. It’s important to note that hepatitis B and C can also be sexually transmitted, but they are usually spread in other ways.

Here are the most relevant STIs along with brief descriptions of their causes:

Chancroid:

This is caused by a species of bacteria that specifically increases the likelihood of getting HIV. It’s extremely rare in the United States and other developed countries.

Chlamydia:

This is the most common curable STI in the US. It’s caused by a specific type of bacteria, Chlamydia trachomatis, which can transform and infect other cells within one’s body.

Genital Herpes:

This is caused by the herpes simplex virus 1 (HSV-1) or 2 (HSV-2). HSV-1 typically results in oral infections, but is now becoming more common as a cause of genital herpes, especially in young and homosexual patients. It’s estimated that around 50 million people in the US are infected with HSV.

Gonorrhea:

This is the second most common STI in the US and is caused by a bacteria called Neisseria gonorrhoeae. This bacteria uses glucose to invade specific cells in the body, and its spread leads to symptoms like inflammation.

Granuloma inguinale:

This is a rare condition in the US, mainly seen in developing countries. It’s caused by a particular different type of bacteria, Klebsiella granulomatis.

HIV and AIDS:

These are caused by a retrovirus that carries two single-stranded RNAs. Early stages of HIV show flu-like symptoms, and the disease usually progresses to AIDS after approximately 11 years. People with HIV are 77 times more likely to get syphilis than the general population.

HPV:

This is the most common sexually transmitted infection worldwide, caused by a double-stranded DNA virus. Certain types of the virus can cause cancer, while other types cause anogenital warts.

Lymphogranuloma venereum:

This is a rare condition in the US caused by a specific type of Chlamydia trachomatis. It’s predominantly seen in tropical and subtropical regions and is highly associated with men who have sex with men and HIV infections.

Mycoplasma genitalium:

After chlamydia, this is the most common cause of urethritis (inflammation of the urethra). Risk factors for this condition include young age, smoking, frequent sexual contact, and having many sexual partners.

Syphilis:

This condition is caused by a specific bacterium, Treponema pallidum, and has different stages classified as primary, secondary, or tertiary. It appears to be on the rise and is more common in developing countries, especially among poorer populations with limited access to healthcare.

Trichomoniasis:

This condition is caused by a single-celled protozoa called Trichomonas vaginalis. It causes direct damage to the epithelium, a layer of cells that lines the outside of the body and internal organs, leading to tiny ulcers primarily in the vagina, cervix, urethra, and glands near the urethra.

Risk Factors and Frequency for Sexually Transmitted Infections

HPV, or the human papillomavirus, is the most common sexually transmitted infection in the US. It’s estimated that around 80% of sexually active people have this infection, including 42% of adults between the ages of 18 and 59. Of the people with HPV, 7% have it in their mouth, and about 14 million new cases are reported each year. According to the CDC, almost everyone who is sexually active and not vaccinated will get HPV at some point. Globally, at least 291 million women have had HPV.

In 2020, the CDC reported about 2.4 million cases of STIs that were not related to HPV in the US. The most common was chlamydia with 1.6 million cases, followed by gonorrhea (677,769 cases) and primary and secondary syphilis (133,945 cases). Congenital syphilis was diagnosed in 2,148 newborn babies, which is a 235% increase from 2016.

Most cases of primary and secondary syphilis are in men, and almost half of these cases are in men who have sex with other men. The CDC estimates that 44% of men who have sex with men and are bisexual and tested positive for syphilis also have HIV. Unfortunately, the overall rate of STIs in the US is increasing.

• Around the world, over 1 million new cases of STIs that can be cured are reported daily, and many don’t show symptoms.
• Each year, it’s estimated that 376 million new infections happen with one of the four curable STIs: chlamydia, gonorrhea, syphilis, and trichomoniasis.
• The most common of these STIs globally is trichomonas, with 156 million new cases annually. Following this is chlamydia (127 million cases), gonorrhea (87 million cases), and syphilis (6.3 million cases).
• The incidence of STIs in the US has increased nearly 30% between 2015 and 2019.
• About 12% of Americans aged 14 to 49 is thought to have herpes now.
• Over 500 million people are estimated to have herpes simplex virus type 2 worldwide.

In 2016, it’s estimated that about one million pregnant women had an STI which resulted in over 350,000 birth or newborn complications. HPV infections cause over 310,000 deaths from cervical cancer each year. Syphilis is the second leading cause of stillbirths all over the world. HIV/AIDS affected about 37 million people worldwide in 2016. Around 15% of individuals with HIV in the US don’t know they have it, and these individuals are responsible for 40% of all new HIV infections. According to the CDC, there are about 35,000 new cases of HIV in the US each year. Mycoplasma genitalium causes 15% to 20% of all non-gonococcal urethritis (NGU), 20% to 25% of all non-chlamydial NGU cases, and 40% of all recurrent or persistent urethritis infections.

Doctors, public health officials, political leaders, and health professionals should ideally have a centralized system for collecting data to analyze and fully understand the occurrence, spread, progression, and treatment of all STIs. Health professionals can refer to various published studies, official government agencies, and health organizations to understand the statistical significance of STIs, such as areas with increasing incidence or specific populations that are affected. STI rates are high in most countries, especially in people aged 15 to 50. Undiagnosed STIs cause an estimated 20,000 cases of infertility in women in the US each year.

Signs and Symptoms of Sexually Transmitted Infections

Medical practitioners are equipped to talk with patients, their partners, and family members about their main health concerns, and to establish a possible set of diagnoses. Whether in a general clinic or an emergency room, taking a thorough medical history is crucial. This is particularly important when dealing with someone who might have a sexually transmitted infection (STI) that hasn’t been diagnosed before. Importantly, in the U.S., anyone aged under 18 has the right to STI screening and treatment without needing permission from their parents.

Healthcare providers need to understand that STIs are often linked to a person’s behavior. This should be addressed during the clinical evaluation in a kind, respectful, and non-judgmental manner. The main roles of medical professionals are to help, treat, and educate patients about their conditions, and to encourage healthy behaviors that help prevent re-infections.

Additional guidance can be sought from individual state healthcare systems or the “Sexually Transmitted Disease Treatment Guidelines 2021” published by the CDC.

When collecting a sexual history, a useful memory aid, known as the “other 5 Ps”, can help guide the questions. This refers to:

• Partners
• Practices

 

• Prevention against pregnancy
• Prior history of STIs
• Protection against STIs

 

The physical exam should be done privately with a chaperone present. Then, after examining the patient, one should ask open-ended questions to make sure there’s good communication and to find out if there are any other details relating to the patient’s sexual practices that were not previously mentioned.

The following is a brief summary of the most common signs, symptoms, and physical exam findings of sexually transmitted infections that can be assessed in an immediate care setting. For a comprehensive approach to these conditions, we recommend the separate StatPearls references.

Below are some of the diagnostic features of certain STIs:

Chancroid:

• Common in people aged 20 to 30, including sex workers and their clients
• Affects genitals and anus, with painful ulcers

Chlamydia:

• Women may have discharge, irregular bleeding, pelvic pain, and frequent urination
• Men may experience urination pain, testicular pain, and rectal inflammation

Genital Herpes:

• Causes systemic symptoms like painful lesions, itching, urination pain, and fevers

Gonorrhea:

• Women may experience urination pain, frequency, pelvic pain, and abnormal bleeding
• Men may experience testicular pain, urination pain, and rectal inflammation

Granuloma Inguinale:

• Causes highly-vascularized, often painless lesions on genitals and anus

HIV:

• May cause a range of systemic symptoms or none at all
• Advanced infection may cause fever, diarrhea, breathlessness, cough, and oral thrush

HPV and Genital Warts:

• Mostly asymptomatic, but may present as warts or malignant ulcerative lesions

Lymphogranuloma Venereum:

• Causes painful lymph nodes in the groin area

Mycoplasma genitalium:

• Women may experience pelvic pain, urination pain, much like gonorrhea or chlamydia
• Men may experience abdominal pain, urination pain, or testicular pain

Pelvic Inflammatory Disease in Women:

• Sexually transmitted infection that affects the female reproductive organs, potentially affecting fertility
• Signs are abdominal tenderness, uterine tenderness, and fever, among others

Syphilis:

• Stages from primary to tertiary, with symptoms varying accordingly

Trichomoniasis:

• Women may experience foul-smelling discharge, itching, painful sexual intercourse, and urination pain
• Men may experience testicular pain, urination pain, or rectal pain

Testing for Sexually Transmitted Infections

The Centers for Disease Control and Prevention (CDC) has released the “Sexually Transmitted Disease Treatment Guidelines 2021”. They offer information to doctors about how to examine and address sexually transmitted infections (STIs). However, it’s ultimately up to your physician to decide which steps to take based on your unique situation.

Generally, if you’re showing signs of an STI, you should also be tested for HIV and other common STIs in your community.

For chancroid (painful ulcers on the genitals), the diagnosis is made by examining your medical history and conducting a physical exam, including ruling out other sources of infection like herpes and syphilis. Ultimately, a definite diagnosis requires growing the specific bacteria in a lab, which can be difficult and is not usually available in most clinics.

For chlamydia, doctors test for the bacteria in a urine sample or using a swab. The same applies to gonorrhea.

Genital herpes diagnosis is based on an examination, and lab tests from a genital ulcer can confirm it. However, patients should also be tested for HIV.

Granuloma inguinale diagnosis requires a visual exam and looking for specific microscopic features. However, getting the infecting microorganism to grow in a lab is challenging.

For HIV, there are tests for antibodies in your blood or saliva. If you are of a certain age or at high risk, you should get tested for HIV at least once a year.

HPV and genital warts are diagnosed primarily through a visual exam. Any suspicious findings can be confirmed through a biopsy.

You can be diagnosed with lymphogranuloma venereum mainly through a clinical examination. That may be confirmed using lab tests if needed.

Pelvic inflammatory disease, an infection of the female reproductive organs, is diagnosed primarily by symptoms. Lab tests are recommended to confirm, and ultrasound may be used in some cases.

Mycoplasma genitalium, a bacteria that can cause infections of the urinary and genital tract, is diagnosed by ruling out chlamydia and gonorrhea and then using specialized lab tests.

Syphilis is confirmed by two separate types of blood tests.

Finally, trichomoniasis, an infection caused by a microscopic parasite, is diagnosed using lab tests of a urine sample or a swab from a genital area.

If you’re pregnant and at risk for STIs, you should be tested for syphilis, HIV, hepatitis B, and hepatitis C at your first prenatal visit. Women at high risk should also be tested for chlamydia and gonorrhea.

In your third trimester, you should be screened again for syphilis, gonorrhea, and chlamydia, and possibly HIV and hepatitis B.

STIs that can be cured with antibiotics should be treated during pregnancy for the benefit of both the mother and the unborn child. Although viral STIs can’t be fully cured, they can be managed with antivirals and other preventive measures during pregnancy to minimize risks.

Treatment Options for Sexually Transmitted Infections

In 2021, the Centers for Disease Control and Prevention (CDC) updated their guidelines for the treatment of Sexually Transmitted Diseases (STDs). These guidelines are tailored to specific groups such as pregnant women, young people, people in prison, men and women who have sex with people of the same sex, and transgender individuals. Each case is unique and should be studied individually to choose the best treatment.

The guidelines suggest primary treatments, but other articles are referenced for additional treatment options. If the primary treatment is not suitable for a patient due to allergies or other reasons, a specialist in infectious diseases or a pharmacist should be consulted for other recommendations.

Below are the specific treatment recommendations for various sexually transmitted infections according to the 2021 CDC STD Treatment Guidelines:

Acute Epididymitis: This is an infection of the epididymis (the tube that carries and stores sperm) usually caused by sexually transmitted bacteria (Chlamydia or Gonorrhea) in young men, while other bacteria might be the cause in older men. The treatment guidelines recommend the use of Ceftriaxone combined with doxycycline for younger men, or Levofloxacin for men older than 35. In cases where the actual cause of the infection is not known, the guidelines recommend a combination of Ceftriaxone and Levofloxacin.

Chancroid: This condition, which usually begins to improve within 1 to 2 weeks of treatment, is characterized by painful sores on and around the genitals. Treatment recommendations include Azithromycin, Ceftriaxone, Erythromycin, or Ciprofloxacin. Patients should check in with their doctor 3 to 7 days after therapy to see how well they are responding to treatment. In some cases, patients may not respond to Erythromycin and Ciprofloxacin due to antibiotic resistance.

Chlamydia: The preferred treatment for Chlamydia is Doxycycline for a week. Alternative treatments include Azithromycin or Levofloxacin, or in pregnant women, Azithromycin or Amoxicillin. If the infection persists, consider testing for and treating Mycoplasma genitalium. You will need to have follow-up testing after treatment.

Genital Herpes: Antiviral treatments like Acyclovir, famciclovir, and valacyclovir are recommended for initial therapy, along with treatments for symptoms such as pain or itching. The treatment plan should be discussed thoroughly between patients and doctors, as the cost can be a burden for some patients.

Gonorrhea: The standard treatment for this bacterial infection is an injection of Ceftriaxone. The choice of drugs will also need to consider the possibility of co-infections with other sexually transmitted diseases. Follow-up tests are recommended after treatment.

Pelvic Inflammatory Disease: The recommended treatment is a combination of Ceftriaxone, Doxycycline, and Metronidazole all taken together. Other treatment options could be considered based on individual cases.

Syphilis: Primary treatment for this infection is with an injection of benzathine penicillin G. An important consideration for pregnant women is that the medication goes directly into the muscles and not into the blood where it can reach the baby. The treatment for patients allergic to penicillin could be Ceftriaxone or doxycycline.

Lymphogranuloma venereum: This condition is relatively rare in the United States and is typically treated with a course of the antibiotic Doxycycline. Other treatment options include Azithromycin and Erythromycin.

Trichomoniasis: It is recommended for patients to take a single dose of Metronidazole orally. Women are advised to take Metronidazole twice daily with food for 7 days. Patients allergic to nitroimidazoles can consider desensitization therapy.

Please note, you should let your doctor know if you’re allergic to any of the named drugs so they can prescribe an alternative.

Guidelines also offer treatment advice for victims of sexual assaults who are at risk of potential infections. It advises emergency contraception, prophylactic antibiotics, testing for hepatitis B, HIV, and HPV.

Finally, when treating STDs, keep in mind that patients may experience the Jarisch-Herxheimer reaction. This reaction, typically occurring within the first 24 hours of initiating antimicrobial therapy for syphilis, sees the patient experiencing fever, chills, aches, and other flu-like symptoms. Syphilis therapy should not be delayed, although fetal monitoring is recommended in late pregnancy to monitor the possible reaction.

What else can Sexually Transmitted Infections be?

When a doctor is assessing a patient, whether in an emergency room or a general check-up, it’s important to consider a wide range of potential issues. This is particularly true when checking for sexually transmitted infections (STIs). STIs can be present in different parts of the body such as the mouth and throat, skin, or genitals.

To start, doctors try to establish an initial diagnostic impression. This is a list of likely diagnoses based on the patient’s symptoms, medical history, and physical examination. The goal is then to confirm this initial diagnosis and discard the other possibilities on the list.

When considering possibilities for STIs, doctors need to evaluate each system in the body separately. These systems include the heart and blood vessels (cardiovascular), lungs (respiratory), stomach and intestines (gastrointestinal), urinary and reproductive organs (genitourinary), brain and nerves (central nervous system), muscles and bones (musculoskeletal), and skin and hair (integumentary).

By matching specific symptoms to each possible STI within these systems, doctors can separate primary infections (the main cause of symptoms) from secondary issues or additional infections.

Here is a list of which STIs might be considered based on the affected body system:

• Cardiovascular: HIV, syphilis, HSV-1/HSV-2 (herpes)
• Central Nervous system: HIV, syphilis, HSV-1/HSV-2, gonorrhea, HPV (human papillomavirus)
• Gastrointestinal: HIV, HSV-1/HSV-2, chlamydia, gonorrhea, HPV
• Genitourinary: HIV, HSV-1/HSV-2, chlamydia, gonorrhea, HPV
• Skin (integumentary system): HIV, HSV-1/HSV-2, chlamydia, gonorrhea, HPV
• Musculoskeletal: HIV, HSV-1/HSV-2, chlamydia, gonorrhea, HPV
• Respiratory: HIV, chlamydia

By using various tools, techniques, and tests, doctors can swiftly determine the correct diagnosis and provide the best care for their patients.

What to expect with Sexually Transmitted Infections

The likelihood of recovery from a specific disease depends on factors like the nature of the disease, how serious it is when first detected, the general health and other medical conditions of the patient, as well as their willingness to follow the treatment plan and take preventive measures.

If the disease is discovered in the early stages and can be dealt with successfully using antibiotics, the outcome will hinge on the treatment process and whether the patient is fully compliant with it. Taking medicines as prescribed is key in treating and managing Sexually Transmitted Infections (STIs).

Unfortunately, around the world, healthcare facilities for diagnosing and treating STIs are often overlooked and lack proper funding. The situation is made worse by issues such as the societal stigma attached to patients with STIs, lack of adequate training for healthcare workers in some places, and limited resources. Patients are often expected to shoulder a large part of the cost for their own treatment, which many are unable to afford.

People who are most at risk—like sex workers, illegal drug users, prisoners, and young people in countries with high STI and HIV rates—frequently do not have access to proper, affordable healthcare and STI treatment services. In many areas of the world, services for STIs are not given the attention or funding they require, leading to higher numbers of people living with untreated infections, insufficient training of healthcare workers, decreased ability to test for these diseases in labs, and inadequate supplies of necessary medications.

Possible Complications When Diagnosed with Sexually Transmitted Infections

Untreated sexually transmitted infections (STIs) often result in widespread infections throughout the body, leading to a lengthy recovery and negative impacts on mental well-being, financial stability, and health in general. The risk of complications rises when there is a lack of adequate public health resources to offer required services and reliable education about safe sex practices. Women are typically more prone to complications from STIs, including widespread infection from untreated pelvic inflammatory disease, sterility, and infertility due to complicated gonorrhea/chlamydial infections.

During pregnancy, STIs can cause increased instances of early labor, premature breaking of the water surrounding the baby (rupture of membranes), infants born underweight, inflammation of the membrane surrounding the baby (chorioamnionitis), miscarriages, stillbirths, and early infant death. Infants can be infected during birth as they are exposed to various infections while passing through the birth canal, leading to particular risks for lung and eye infections. Infants born to mothers with untreated syphilis may develop issues in multiple organs, including bones, brain, ears, eyes, heart, skin, and teeth. Certain types of the Human papillomavirus (HPV) strain are associated with an increased risk of cancers, especially in women. If not managed appropriately, HIV infections can progress to AIDS, a potentially fatal late-stage complication due to a severely weakened immune system.

Healthy Sex Practices:

• Maintain regular and thorough STI testing
• Ensure awareness and usage of safe sex practices
• Pregnant individuals should undergo thorough STI testing
• Newborns exposed to STIs during birth should receive immediate care

Preventing Sexually Transmitted Infections

Doctors should be well-versed in the most common sexually transmitted diseases (STDs) in their area. They should also be comfortable advising their patients about changes they can make in their personal behavior to reduce their risk. It’s important that patients receive all the necessary information about preventing, treating, and counseling for sexually transmitted infections.

The HPV Vaccine is widely used and proven to be more than 99% effective. It requires 2 shots, given 6 to 12 months apart. According to health regulations, these shots can be given starting at age 9, but are most effective at ages 11 to 12. They are recommended for everyone who hasn’t been vaccinated by age 26.

The vaccine is not universally recommended for individuals between 27 and 45 years old, but may be reasonable for those at high risk for HPV infections. As you get older, the benefits of getting vaccinated against HPV decrease. After age 45, vaccinations are not generally recommended as most people have already been exposed to HPV and there isn’t much benefit.

HIV Pre-Exposure Prophylaxis, or PrEP, is not a vaccine but a preventive measure against HIV. It’s 99% effective in stopping HIV infections in people who take the medication as directed. It is most suitable for people who are at high risk for HIV, like those with multiple sexual partners or those in open relationships. You must first test negative for HIV-1 and then keep testing negative every 3 months (or every 2 months if you’re receiving injections).

Out of the 1.2 million people in the U.S. who are at high risk for HIV and hence, should be taking PrEP, only about 25% actually are. Following the treatment guidelines strictly is crucial for the medicine to provide its protective effects. PrEP isn’t considered enough on its own for treating active HIV infections and won’t prevent other STDs. The current recommended PrEP treatments include certain oral medications and injectable drugs.

Doxycycline Post-Exposure Prophylaxis is a treatment taken after exposure, preferably within 24 to 72 hours of unprotected sexual contact. This treatment has been shown to lower the risk of getting chlamydia, gonorrhea, and syphilis by about two-thirds in a study of over 500 patients. This preventive treatment is currently suggested for high-risk groups, such as men who have sex with men and have multiple partners. This approach has been adopted in San Francisco, which has seen a significant decrease in STDs by about 50%.

However, concerns have been expressed regarding possible side effects, the unknown effects of long-term use, and if widespread use of this type of preventive treatment might lead to bacteria that are resistant to antibiotics. The medical community is still discussing who should be offered this kind of treatment. The American health regulatory body, the CDC (Center for Disease control) is currently reviewing the matter and will publish guidelines. Given the increasing rates of STDs around the world (especially syphilis), more effective approaches for prevention and treatment are needed.