Can STIs cause diarrhoea?

Many sexually active people assume that sexually transmitted infections (STIs) only affect the genital area. While symptoms like Genital Warts, unusual discharge, lesions, and chancres might prompt a visit to a sexual health clinic, STIs can also present with lesser-known symptoms.

While it may surprise some people, diarrhoea can be a common sign of an STI.

If you’re experiencing diarrhoea and think a sexually transmitted disease might be causing it, keep reading to find out more.

Are you concerned about an STI? Get tested with Better2Know.

What is diarrhoea?

Diarrhoea is loose, watery, and frequent passage of stool that can often be accompanied by other symptoms, such as:

• Lower abdominal pain
• Bloating
• Nausea
• Vomiting
• Fever
• Bloody stool
• Mucus in the stool
• An urgent need to defecate

Acute diarrhoea

Most cases of diarrhoea are acute. In these cases, diarrhoea results from your body’s response to certain foods, viruses, bacteria, and other foreign agents.

Common causes of diarrhoea include:

• Viral infections (the flu, norovirus, rotavirus, etc)
• Bacterial infections (e.coli, c. difficile, etc)
• Medicines, including many antibiotics and antiviral medications
• Fructose, which can be found in many fruits and honey
• Artificial sweeteners

These cases of diarrhoea are usually temporary and go away once the underlying cause is corrected (i.e., the infection passes or is cured, or any foods you ingest are changed).

Chronic diarrhoea

Chronic diarrhoea, often caused by digestive disorders, may require treatment or lifestyle changes. Chronic diarrhoea is a common symptom of:

• Irritable bowel syndrome (IBS)
• Crohn’s Disease
• Pancreatitis
• Colitis
• Food intolerances

Are there STIs that cause diarrhoea?

While many people may not associate diarrhoea with sexually transmitted infections, it can be a more common symptom than you might expect.

Here are a few infections that can cause or are associated with diarrhoea.

HIV

Human Immunodeficiency Virus (HIV) damages the immune system by compromising your body’s ability to produce T-cells. If left untreated, HIV can progress slowly over several years and develop into AIDS.

Diarrhoea is one of the most common symptoms of an HIV infection. The severity of the diarrhoea can vary from person to person. It can appear during an acute HIV infection in the first few days and weeks. Other symptoms of an acute HIV infection include:

• Fever
• Nausea
• Night sweats
• Headaches
• Joint pain
• Sore throat
• Swollen lymph nodes

Diarrhoea can also be caused by HIV medications. Antiretroviral medications, which are often used to treat HIV, often carry a risk of diarrhoea.

People with HIV also commonly experience gastrointestinal problems, resulting from a compromised immune system. Common gastrointestinal problems during HIV include:

• Intestinal infections, such as:
  • Mycobacterium avium
  • Cryptosporidium
• Bacterial overgrowth within the digestive tract
• HIV enteropathy

Gonorrhoea

Gonorrhoea is a bacterial STI transmitted through unprotected vaginal, anal, or oral sex.

While Gonorrhoea infections are most common in the genital area, it’s possible to get the infection in your rectum. This usually results from unprotected anal sex and sharing sex toys.

People with an anal Gonorrhoea infection may experience proctitis, an inflammation of the rectum that is associated with pain and itching around the anus, painful bowel movements, and unusual discharge from the rectum.

While Gonorrhoea doesn’t cause watery stools, it can cause symptoms often seen alongside diarrhoea, including blood and mucous in the stool and an urgent need to pass stool.

Chlamydia

Like Gonorrhoea, you can also get a Chlamydia infection in your rectum, also through unprotected anal sex and sharing sex toys.

A Chlamydia infection in the rectum can result in similar symptoms of proctitis, including inflammation and pain around the rectum, painful bowel movements, and unusual discharge from the anus. 

Like with Gonorrhoea, Chlamydia will be unlikely to cause watery stools. However, it will cause the same irritation and urgent need to defecate.

Syphilis

While they are very rare, there have been reported cases of Syphilis causing lower gastrointestinal symptoms, such as diarrhoea, where Syphilis spirochetes were found in the gastrointestinal tract of infected people.

These cases usually occur in men who have sex with men and trans women who receive anal sex. In many of these cases, gastrointestinal issues were attributed to conditions like inflammatory bowel disease, allowing the infection to progress and damage the patient’s health.

While diarrhoea isn’t normally caused by Syphilis, including a Syphilis test in an STD screen would be prudent for those concerned.

Herpes

Like with the above examples, getting an anal Herpes infection in your rectum can result in diarrhoea in some circumstances.

HSV colitis is a rare but severe complication of inflammatory bowel syndrome (IBS). Immunosuppressant drugs are often used to treat IBS, and the reduced immune function can leave certain patients at risk for developing opportunistic infections.

 An anal HSV infection, contracted by someone with IBS, can exacerbate GI symptoms, causing watery stool, blood in stool, abdominal pain, fever, and nausea.

How do you know if an STI causes your diarrhoea?

Having diarrhoea doesn’t necessarily mean you’ve contracted an STI. Due to the complexity of these infections, diagnosing an STI based on a single symptom is nearly impossible.

However, if you experience diarrhoea, it may indicate an STI. In such cases, getting tested is essential to ensure your health and well-being.

Final thoughts

Get tested for HIV, Chlamydia, Gonorrhoea, Syphilis, and Herpes with Better2Know. Book a test at a sexual health clinic near you or get tested from the comfort of your own home with our wide range of Home Test Kits.

Don’t leave your sexual health to chance. Get tested at a sexual health clinic near you.

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