Rectal STIs: Symptoms, Causes & When to Get Tested

Rectal STIs: Symptoms, Causes & When to Get Tested

Experiencing rectal symptoms can be concerning, and it is natural to wonder whether they might be related to a sexually transmitted infection. Rectal STI symptoms — such as pain, discharge, or discomfort in the anal area — can be caused by several different infections, but it is equally important to recognise that not all anal symptoms are related to STIs. Other common conditions, such as haemorrhoids or fissures, can produce similar symptoms. Understanding what rectal STIs are, how they present, and when testing may be appropriate can help you make informed decisions about your health. In this article, we explain the symptoms and causes of rectal STIs, how testing is carried out, and when it may be worth seeking clinical advice — all in a clear, discreet, and non-judgemental way.

What Is a Rectal STI?

A rectal STI is a sexually transmitted infection that affects the tissue of the rectum and anal canal. Several common STIs can infect this area, and rectal infections are more common than many people realise.

Rectal STIs are most commonly associated with receptive anal sexual contact, but transmission can also occur through other forms of intimate contact involving the anal area. The specific route of transmission depends on the infection involved.

An important point to understand is that rectal STI infections may occur even without obvious symptoms. Many people with a rectal chlamydia or gonorrhoea infection, for example, experience no noticeable symptoms at all. This means that testing based on exposure history — rather than symptoms alone — can be an important part of comprehensive sexual health screening.

Common Rectal STI Symptoms

When rectal STI symptoms do occur, they may include:

• Rectal pain or discomfort — a persistent ache or soreness in the anal area that does not resolve on its own
• Discharge from the anus — this may be mucous-like, cloudy, or occasionally blood-tinged
• Light bleeding or spotting — particularly during or after bowel movements
• Itching or irritation — localised to the anal area
• A feeling of fullness or pressure in the rectum — sometimes described as a persistent urge to pass a bowel movement
• Pain during bowel movements — discomfort that may range from mild to moderate

It is important to note that these symptoms may be mild, intermittent, or entirely absent. The severity of symptoms does not always reflect the seriousness of the underlying infection. In some cases, a rectal STI may be present without any noticeable symptoms at all, which is why exposure-based screening can be valuable.

Which STIs Can Affect the Rectum?

Several common STIs can infect the rectal area. Below is an overview of the most relevant infections.

Rectal Chlamydia

Chlamydia is one of the most common rectal STIs. Rectal chlamydia is frequently asymptomatic — meaning that many people who carry the infection in the rectum are unaware of it. When symptoms do occur, they may include mild rectal discharge, discomfort, or occasional bleeding. Because rectal chlamydia often produces no symptoms, testing based on exposure history is important for detection.

Rectal Gonorrhoea

Gonorrhoea can also infect the rectum and is another common rectal STI. Rectal gonorrhoea may cause discharge from the anus, soreness, discomfort, or a sensation of rectal fullness. As with chlamydia, rectal gonorrhoea can also be asymptomatic in some cases. Laboratory NAAT testing on a rectal swab is the standard method of detection.

Syphilis

Syphilis can affect the anal area, particularly during its early stages. A primary syphilis infection may present as a painless ulcer (chancre) around or inside the anus. These sores can be easy to miss, especially if located internally. In later stages, syphilis can cause more widespread symptoms. For a detailed overview, read our guide on early vs late syphilis symptoms.

Herpes (HSV)

Herpes simplex virus can cause painful blisters or sores around the anal area. These lesions may be accompanied by itching, burning, or general discomfort. Herpes outbreaks can recur, as the virus remains in the body after the initial episode. For more information about appearance and recognition, see our guide on what herpes looks like.

HPV (Human Papillomavirus)

HPV can cause genital or anal warts — small growths that may appear around or inside the anus. Not all HPV infections cause visible warts; some strains are associated with cell changes that may require monitoring. HPV is transmitted through skin-to-skin contact and is one of the most common sexually transmitted infections overall.

Rectal STI Symptoms vs Other Causes

It is important to recognise that not all rectal or anal symptoms are caused by sexually transmitted infections. Several non-STI conditions can produce similar symptoms, and appropriate assessment can help clarify the cause.

Common non-STI causes of rectal symptoms include:

• Haemorrhoids — swollen blood vessels in the anal area that can cause bleeding, itching, and discomfort. Haemorrhoids are very common and are not related to sexual activity.
• Anal fissures — small tears in the lining of the anal canal, often caused by passing hard stools. These can cause pain and bleeding during bowel movements.
• Irritation — the anal area can become irritated by hygiene products, dietary factors, or friction, leading to itching or discomfort.
• Inflammatory bowel conditions — conditions such as Crohn's disease or ulcerative colitis can cause rectal symptoms including pain, bleeding, and discharge.
• Fungal infection — localised fungal infections can cause itching and irritation around the anal area.

If you are experiencing rectal symptoms and are unsure of the cause, a clinical assessment can help determine whether STI testing, further investigation, or simple reassurance is appropriate.

When Should You Consider Testing?

Rectal STI testing may be appropriate in several circumstances. Testing is worth considering if:

• You have had receptive anal sexual contact with a new or casual partner — particularly if barrier protection was not used
• You are experiencing any of the symptoms described above, such as rectal pain, discharge, bleeding, or itching
• A sexual partner has been diagnosed with an STI — partner notification is an important part of managing STI transmission
• You have multiple sexual partners — routine screening at relevant body sites may be recommended depending on your sexual history
• You would like routine screening as part of a comprehensive sexual health check

Testing decisions are best guided by your individual exposure history and any symptoms you may be experiencing. A clinician can help determine which tests are appropriate for your situation.

How Is Rectal STI Testing Done?

Rectal STI testing is typically straightforward and involves a rectal swab. This can be performed in two ways:

• Self-collected swab — many clinics offer the option to collect the swab yourself in private, with clear instructions provided
• Clinician-collected swab — in some cases, a healthcare professional may collect the sample, particularly if a clinical examination is also required

The swab is then sent to an accredited laboratory for NAAT (nucleic acid amplification test) analysis — the same highly sensitive testing method used for genital chlamydia and gonorrhoea screening.

The process is usually quick and causes only brief, mild discomfort. Many people find it less uncomfortable than expected. Results are typically available within a few working days, depending on the laboratory and clinic.

What If You Have No Symptoms?

As mentioned above, many rectal STIs — particularly chlamydia and gonorrhoea — can be completely asymptomatic. This means that the absence of symptoms does not rule out infection.

If your sexual history includes receptive anal contact, screening at the rectal site may be advisable even if you feel well. Standard genital testing (such as a urine test or genital swab) will not detect a rectal infection — site-specific testing is required.

Routine rectal screening is particularly recommended for individuals with multiple partners or those who have had contact with a partner diagnosed with an STI. For more about infections that may present without symptoms, read our guide on asymptomatic STDs.

Can Rectal STIs Be Treated?

The treatment outlook for rectal STIs depends on the type of infection:

• Bacterial infections — rectal chlamydia, gonorrhoea, and syphilis are usually treatable with appropriate antibiotics prescribed by your GP or sexual health clinician. The specific antibiotic and course length may vary depending on the infection and any resistance patterns. Follow-up testing (a test of cure) may be recommended for gonorrhoea in particular.
• Viral infections — herpes and HPV are managed rather than cured. Antiviral medication prescribed by your GP or sexual health clinician can help manage herpes outbreaks and reduce their frequency and severity. HPV-related warts can be treated, and in many cases the immune system clears HPV naturally over time. Monitoring may be recommended in certain situations.

Early detection through appropriate testing allows your GP or sexual health clinician to start treatment promptly, reducing the risk of complications and onward transmission.

Can You Prevent Rectal STIs?

While no prevention method eliminates risk entirely, several practical measures can significantly reduce the likelihood of acquiring a rectal STI:

• Condom use — using condoms during anal sexual contact substantially reduces the risk of STI transmission, though it does not eliminate risk completely for all infections — particularly those spread through skin-to-skin contact. For more on this topic, read our guide on can you get STDs while using a condom.
• Regular testing — routine screening at appropriate body sites allows early detection and treatment, reducing the risk of unknowing transmission.
• Open communication — discussing sexual health, testing history, and STI status with partners supports informed decision-making.
• Avoiding sexual contact when symptomatic — if you or a partner are experiencing symptoms such as sores, discharge, or unusual discomfort, avoiding sexual contact until assessment and testing have been completed is advisable.

Prevention is about reducing risk through practical, consistent measures rather than relying on any single strategy.

Frequently Asked Questions

Can you have a rectal STI without symptoms?

Yes. Many rectal STIs — particularly chlamydia and gonorrhoea — are frequently asymptomatic. This means you can carry an infection without experiencing any noticeable symptoms. If your sexual history includes receptive anal contact, screening at the rectal site may be appropriate even in the absence of symptoms.

Is rectal STI testing painful?

Rectal STI testing involves a small swab and is generally quick and only mildly uncomfortable. Many clinics offer self-collection, allowing you to take the sample yourself in private. Most people find the process less uncomfortable than they anticipated.

Do I need a rectal swab if I had anal sex?

If you have had receptive anal sexual contact, a rectal swab is the appropriate way to test for infections at that site. A standard urine test or genital swab will not detect a rectal infection. Your clinician can advise on which tests are suitable based on your exposure history.

Can rectal STIs spread to other parts of the body?

In general, a localised rectal infection remains at the site of infection. However, some STIs — such as syphilis and HIV — can have systemic effects if left untreated. Additionally, it is possible to have concurrent infections at multiple sites (for example, genital and rectal). Comprehensive testing at all relevant sites ensures that infections are not missed.

How soon after anal sex should I test?

The recommended testing time depends on the infection. For chlamydia and gonorrhoea, testing is generally reliable from around 7–14 days after exposure. For HIV (4th generation test), the window period is 18–45 days. For syphilis, reliable testing is typically possible from 3–6 weeks after exposure. Your clinician can advise on the most appropriate timing based on your circumstances.

When to Seek Medical Advice Urgently

While most rectal STI symptoms can be assessed through a routine clinical appointment, you should seek prompt medical advice if you experience:

• Severe pain — significant or worsening rectal or anal pain that does not improve with time
• Heavy bleeding — rectal bleeding that is more than light spotting, or that persists
• Fever accompanied by a rash — this combination may indicate a systemic infection requiring clinical assessment
• Rapidly worsening symptoms — any symptoms that are becoming significantly worse rather than improving

These symptoms do not necessarily indicate a serious condition, but prompt assessment ensures that appropriate care is provided without unnecessary delay.

Confidential Rectal STI Testing in the UK

If you are experiencing rectal symptoms or would like confidential screening following anal sexual contact, appointments are available at our UK clinic. Testing decisions should consider your exposure history and timing.

Whether you are looking for site-specific screening, follow-up testing, or guidance on next steps, our nurse-led team provides discreet, non-judgemental testing support tailored to your individual needs. If treatment is required, we will advise you on the appropriate next steps with your GP or sexual health service. Book a confidential appointment at a time that suits you.