Strep Throat vs Chlamydia: How To Tell Them Apart?

Sore throat, difficulty swallowing, and swollen lymph nodes are all symptoms that can indicate a variety of infections, including strep throat and chlamydia. While these two conditions share some similarities, they are fundamentally different, and it's important to tell them apart to receive appropriate treatment. 

This blog post will explore the key differences between strep throat and chlamydia, including their causes, symptoms, diagnostic methods, and treatments. By the end of this article, you'll better understand these two conditions and be better equipped to identify and treat them if you or someone you know experiences symptoms.

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Strep throat, caused by the strep A bacteria, is a common cause of sore throats. However, in some cases, people can be infected with chlamydia. This can also cause a sore throat, and knowing the difference is important.


Chlamydia is caused by a bacterium in the Chlamydia family. In this case, we are talking about Chlamydia trachomatis, which typically infects the genitalia. 

  •  While sexually transmitted infections typically affect the genitals, they can affect the throat if you are having oral sex, regardless of the gender or genitalia of your partner. However, the risk is much less than genital sex, as Chlamydia trachomatis prefers genital colonization.

Chlamydia trachomatis can be a serious condition. It can lead to blindness, fertility problems, inflammation of the pelvis, and arthritis resulting from sexually transmitted infections. However, as a throat infection, it is mild, commonly asymptomatic, and clears within a few weeks. It is most commonly seen in men who have sex with men and transwomen who have sex with men. 

When it does have symptoms, they include a sore throat, dental problems, pain, and sores in and around the lips and mouth.

Strep throat

Strep throat is a common infection caused by strep A bacteria. This is very contagious and also spreads through respiratory droplets and direct contact. It can occasionally be transmitted by poor food handling.

Typically, symptoms include:

  • Sore throat

  • Fever

  • Pain when swallowing

  • Red and swollen tonsils

  • Petechiae, which are tiny red spots that can appear anywhere but are seen on the roof of the mouth with strep throat

  • Swollen lymph nodes in the front of the neck

Other symptoms include headache, stomach pain, nausea, and/or vomiting, although these are less common.

Signs and symptoms

Strep throat can be distinguished from chlamydia symptomatically. Both infections result in a sore throat. It's worth noting, however, that chlamydia does not typically cause pain when swallowing, red and swollen tonsils, and/or petechiae or swollen lymph nodes. Infection with Chlamydia trachomatis is often asymptomatic.

Strep throat does not typically cause a stuffy or runny nose, fatigue, cough, or hoarseness.

There are, obviously, other respiratory infections that can be mistaken for either of these conditions. Chlamydia, in particular, can be mistaken for a cold, although the symptoms drag on and last longer.

Both infections can occur asymptomatically, but asymptomatic carriers are much less likely to pass on the condition.


The gold standard for diagnosing strep throat is taking a swab at the back of the throat and then sending this throat swab to a lab to be cultured and viewed. However, many offices use rapid antigen testing to start antibiotic treatment sooner if the test is positive. 

A negative antigen test, however, does not necessarily mean you don't have a strep throat infection. The lab test is more accurate, but the downside is that this test takes time.

Chlamydia pneumoniae, another species of the genus Chlamydia, is also diagnosed by a lab test — either a throat swab or a blood test. These tests can take a few days to get back. However, there is no approved test for Chlamydia trachomatis in the throat.

Depending on your symptoms, your doctor might test for multiple infections. Again, though, it is often possible to tell the difference based on the symptoms you are experiencing, and your doctor might not, for example, test for strep throat if you have a stuffy nose.

As Chlamydia trachomatis is sexually transmitted, your doctor might suspect it if your sexual history or behavior puts you at high risk or if you have symptoms of a sexually transmitted infection too. This includes men and transwomen who have sex with men and people who have multiple partners or routinely have sex with strangers. You cannot catch Chlamydia trachomatis easily by other means, so it can be excluded based on sexual history, but you must be honest with your doctor.


Strep throat is typically treated with antibiotics. In adults, strep throat typically self-resolves without treatment. In children, however, if untreated, it risks developing rheumatic fever (which can lead to long-term heart problems if untreated).

Most cases of Chlamydia pneumoniae also resolve on their own. However, it can lead to serious complications, including swelling of the brain or heart and worsening asthma. Because of this, doctors may prescribe antibiotics, especially if you have asthma. The typical first-line therapy is azithromycin.

Chlamydia trachomatis is also treated with antibiotics. You should not have sex for at least seven days after taking a dose of antibiotics, or the end of your course, whichever is later. While the infection typically resolves on its own, you are at risk of passing it on to others who may get the more serious genital manifestation of the sexually transmitted infection.


The best way to prevent yourself from getting strep throat or Chlamydia pneumoniae is to practice good hand hygiene. If coughing or sneezing, cough into a tissue or an elbow, not your hand. Avoid close contact with anyone who is sick if possible. Wash your hands regularly, too, if you are unwell.

You can prevent Chlamydia trachomatis by using a condom or dental dam (you can make a dental dam out of a condom) any time you have oral sex, especially if you are not monogamous.


Strep throat can lead to rheumatic fever in children if untreated. It can cause long-term heart problems called rheumatic heart disease, which causes a lot of morbidity and mortality for the rest of your life.

The biggest risk with Chlamydia trachomatis in the throat is passing the infection on to others. If you give oral sex, you can transmit it to the genitalia, where it is more serious.

The lowdown

While chlamydia and strep throat cause a sore throat, the other symptoms caused are often different. This means you can tell which you have based on symptoms alone. Your doctor can help determine which infection you most likely have and may take a throat swab to test for bacteria.

The typical treatment for all these infections is with antibiotics, although the antibiotics used are different. You should always finish the course of antibiotics and take the recommended precautions to keep from passing the infection to others. It is always best to see a doctor for an accurate diagnosis and treatment plan if you have symptoms.

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