Sexually transmitted infections (STIs) are a group of infections transmitted through sexual contact. These infections can affect various parts of the body, including the skin, mouth, and digestive tract. While diarrhea is commonly associated with foodborne illnesses, it can also be a symptom of certain STIs, indicating a broader impact on systemic health.
STDs That Can Cause Diarrhea
Several sexually transmitted infections have the potential to cause diarrhea, either directly or indirectly, through their impact on the digestive system.
Human Immunodeficiency Virus (HIV) can induce diarrhea during the acute seroconversion phase, shortly after infection as the immune system reacts. In later stages, chronic diarrhea may arise from opportunistic infections that target individuals with weakened immune systems, such as Cryptosporidiosis or Mycobacterium avium complex (MAC) infection, which inflame the intestines.
Syphilis, a bacterial infection, can in rare cases lead to gastrointestinal manifestations, including diarrhea, especially if the infection progresses to later stages affecting various organs. While not a typical symptom, tertiary syphilis may involve the stomach or intestines, causing inflammation and altered bowel function. Such instances are less common but highlight the systemic reach of untreated syphilis.
Gonorrhea and Chlamydia, common bacterial STIs, can cause proctitis, an inflammation of the rectal lining, when transmitted through anal sex. This inflammation often leads to symptoms such as rectal pain, discharge, and a feeling of incomplete bowel movements, which can manifest as or contribute to diarrhea. The bacteria directly irritate the rectal tissues, disrupting normal bowel function.
Herpes Simplex Virus (HSV), while primarily known for causing sores, can also affect the anal and rectal areas, leading to discomfort and pain. Although HSV does not directly cause diarrhea, the intense pain and inflammation associated with anal or rectal herpes can alter bowel habits, making defecation difficult and potentially leading to changes in stool consistency. This indirect effect on bowel movements can be a source of distress.
Beyond traditional STIs, certain enteric infections can also be transmitted sexually, particularly through oral-anal contact. These include parasitic infections like Giardia lamblia, which causes giardiasis, and bacterial infections such as Shigella and Entamoeba histolytica, which causes amoebiasis. These pathogens directly infect the intestines, leading to inflammation, abdominal cramps, and persistent watery diarrhea, often accompanied by fever and nausea.
Diagnosis and Treatment
Diagnosing STIs that may cause diarrhea requires a medical evaluation, as symptoms can overlap with other conditions. A healthcare provider will begin with a detailed medical history, including sexual activity, followed by a physical examination. Depending on the suspected infection, various tests may be ordered to confirm the diagnosis.
Blood tests are used to detect antibodies for HIV and syphilis, indicating the presence of these infections. For suspected rectal infections like gonorrhea and chlamydia, swabs may be taken from the rectum to identify the specific bacteria. Stool samples are collected to test for parasitic or bacterial enteric infections such as Giardia, Shigella, or Amoebiasis.
Treatment for STIs causing diarrhea varies based on the pathogen identified. Bacterial infections like gonorrhea, chlamydia, and syphilis are treated with antibiotics. For example, a single dose of ceftriaxone is used for gonorrhea, while azithromycin or doxycycline can treat chlamydia. It is important to complete the entire course of antibiotics, even if symptoms improve, to ensure the infection is fully eradicated and to prevent antibiotic resistance.
Viral infections, such as HIV and herpes, are managed with antiviral medications, which help control the virus but do not cure the infection. Antiretroviral therapy (ART) for HIV can suppress the viral load, improving immune function and reducing opportunistic infections that cause diarrhea. Antiviral medications for herpes can reduce the frequency and severity of outbreaks. Parasitic infections like giardiasis or amoebiasis are treated with antiparasitic medications, such as metronidazole or tinidazole. Following up with a healthcare provider after treatment is recommended to confirm the infection has cleared or is adequately managed.
Prevention and When to Seek Medical Attention
Preventing STIs that can cause diarrhea involves safer sexual practices. Consistent and correct use of condoms during sexual activity reduces the risk of transmission. Limiting the number of sexual partners also lowers exposure to potential infections. Regular STI testing is important for sexually active individuals, as many infections can be asymptomatic, meaning they show no visible signs, yet can still be transmitted.
Vaccinations are available for some STIs, such as the HPV vaccine, though it does not directly prevent the infections discussed. Open communication with sexual partners about STI status and testing history is a protective measure. If you experience persistent diarrhea, especially if it is accompanied by other symptoms like rectal pain, discharge, unexplained weight loss, or if you have recently engaged in unprotected sexual activity, seek medical attention. Early diagnosis and treatment are important for managing symptoms, preventing complications, and avoiding further transmission.