What you need to know about eye syphilis

Hannah Millington
·Health & Wellness Reporter
·7-min read
Syphilis - male's eyes with bloodshot symptoms. (Getty Images)
Syphilis can typically be cured if caught and treated promptly. (Getty Images)

While syphilis may sound like a sexually transmitted infection (STI) from the stone age (and once was), the reality is it's on the rise now, and a lack of understanding could result in serious consequences.

Far from 'just' an STI, syphilis can cause irreversible long-term health effects if left untreated. So while it may not be as common as chlamydia or gonorrhoea, we should be aware of the risks.

Very much alive and thriving, cases of syphilis in England were at their highest levels in 75 years in 2022, soaring to nearly 8,700, the most since 1948. Meanwhile over in the US, at the end of November a cluster of five cases of ocular (eye) syphilis were identified in women with a common male sex partner, suggesting an unidentified strain of the bacteria that causes it might have been a risk factor.

But with syphilis typically hard to identify straight away, here's everything we know about the STI, including how it can affect the eyes.

What is syphilis?

"Syphilis is a sexually transmitted infection (STI) that can be very dangerous if it is not treated. Around 75% of syphilis cases are found in men who have sex with other men, but heterosexual men and women can also catch the disease," says Dr Babak in partnership with Superdrug Online Doctor.

"The good news is that syphilis is easy to treat, but you will have to get tested first." As well as buying from a pharmacy, you may be able to order a self-test kit online for free from your local STI testing and treatment service or sexual health clinic.

In response to it often dubbed a 'mediaeval STI', Dr Babak adds: "This is more of a historical reference and may not accurately capture the current understanding of syphilis as a contemporary health issue. In modern times, syphilis is a treatable infection, but its persistence and resurgence highlight the ongoing challenges in preventing and managing STIs in various communities."

Treponema pallidum syphilis bacterium, computer illustration.
Syphilis is caused by the bacteria Treponema pallidum. (Getty Images)

Syphilis symptoms

"Syphilis symptoms tend to change over time, making them tricky to identify," say the experts at Condoms UK. They are also often mild and hard to notice.

"Common signs include painless sores or ulcers on the genitals, mouth, or hands, along with white or grey warty growths and rashes on the palms or soles. Some may experience flu-like symptoms, swollen glands, and patchy hair loss, which might not appear until weeks after being exposed."

Sometimes symptoms of syphilis can improve or go away completely, but if you haven't been treated, then the infection is still in your body, meaning you can still pass it on and you're at risk of serious problems later on.

A man has just woken up in a domestic environment, either a living room or a bedroom. He is cozy in duvets and pillows. He rubs his eyes and face sleepily as he comes to.
It can take three weeks or more for syphilis symptoms to appear after you're infected. (Getty Images)

How can syphilis affect the eyes?

Some of the ways syphilis can impact the eyes, according to Dr Babak, include:

  • Uveitis: Syphilis can cause inflammation that includes the iris, ciliary body, and choroid. Uveitis can lead to symptoms such as eye pain, redness, sensitivity to light, and blurred vision

  • Chorioretinitis: Inflammation of the choroid and retina can occur, leading to a condition known as chorioretinitis. This can result in visual disturbances and may lead to permanent vision loss if not treated promptly

  • Optic neuritis: This is where syphilis causes inflammation of the optic nerve, which transmits visual information to the brain. Optic neuritis may result in vision problems, including blurry or reduced vision

  • Conjunctivitis: In some cases, syphilis can lead to inflammation of the conjunctiva, the clear membrane covering the white part of the eye and the inside of the eyelids. Conjunctivitis can cause symptoms such as redness, itching, and discharge from the eyes

What is ocular syphilis?

"Ocular syphilis is a manifestation of syphilis that specifically involves the eyes and surrounding structures. It is not a different form of syphilis but rather a complication of the infection," Dr Babak explains.

"Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum, and it can affect various organs and systems in the body, including the eyes," says Dr Babak.

Ocular syphilis is a serious complication requiring prompt medical attention. "Diagnosis involves a combination of clinical evaluation, blood tests, and sometimes cerebrospinal fluid analysis [a group of lab tests measuring chemicals in this liquid surrounding the brain and spinal cord]. Treatment typically includes antibiotics, such as penicillin, to eliminate the bacteria responsible for syphilis.

"Early detection and treatment are crucial to prevent severe eye damage and complications. If you suspect you have syphilis or are experiencing eye-related symptoms, it's important to seek medical attention for proper diagnosis and treatment."

The experts at Condoms UK add, "In the case of ocular syphilis, distinct symptoms include pain, redness, floating spots, sensitivity to light, and blurred or loss of vision."

Blood sample with syphilis positive
If you suspect you have syphilis you will need to do a test. (Getty Images)

Treating syphilis

"The primary treatment for syphilis is antibiotics, with penicillin being the preferred choice," says Dr Babak.

He explains the specific treatment plan depends on the stage of syphilis, which include:

  • Primary and secondary syphilis: Intramuscular injection [into the muscle] of benzathine penicillin G is the standard treatment

  • Early latent syphilis: Benzathine penicillin G is also used

  • Late latent syphilis and tertiary syphilis: Treatment involves a longer course of intramuscular penicillin

  • Neurosyphilis or ocular syphilis: Intravenous penicillin is often recommended, as it can better penetrate the central nervous system

"It's crucial to note that penicillin is the recommended treatment, and alternatives may be considered for individuals allergic to penicillin. However, the choice of alternative antibiotics would depend on the specific circumstances and the guidance of a healthcare professional," Dr Babak adds.

"It's essential for individuals diagnosed with syphilis to follow their healthcare provider's advice regarding the appropriate antibiotic treatment and the necessary follow-up care. Regular monitoring and testing are often recommended to ensure the infection is adequately treated."

You should avoid sex until both you and a sexual partner have finished treatment and tests have shown it has worked.

Woman talking to doctor at sexual health clinic
Speak to your sexual health clinic or GP if you or a sexual partner might have syphilis. (Getty Images)

Dangers of syphilis

"While prompt treatment with antibiotics is generally highly effective in curing syphilis, successful treatment does not undo any damage that may have occurred before diagnosis, especially in the case of late-stage or tertiary syphilis," Dr Babak flags.

"Regular follow-up and testing are typically recommended to ensure that the infection has been completely eradicated."

And what are the long-term consequences if left untreated? "Syphilis can lead to serious complications affecting various organs and systems, including the heart, brain, and nervous system."

The Condoms UK experts expand further, "If left untreated, it can cause heart problems like angina, aortic aneurysm, or heart failure. Brain problems might include seizures, memory difficulties, and even personality changes. Nerve issues like shooting pains, joint pain, and damage to the joints can arise. It can affect the skin, bones, testicles, liver, and other organs, leading to complications across the body."

And remember, even if symptoms improve or disappear, the infection remains in your body. "The recent case in Michigan, where one man transmitted the infection to five women, illustrates this alarming reality of how easy it is to pass on."

Preventing syphilis

Condoms UK urge, "We advise the public to be vigilant and seek medical attention if you experience any symptoms of syphilis. We also advise that you use condoms during sexual activity to reduce the risk of contracting syphilis and other sexually transmitted infections.

"Early detection and treatment are crucial in preventing the potentially devastating long-term effects of syphilis."

The NHS also advises using a condom when you have vaginal or anal sex, using a condom to cover the penis or a latex or plastic square (dam) to cover the vagina if you have oral sex, and making sure you complete treatment if you or your partner have syphilis.

It urges avoiding sharing sex toys (or washing and covering them with a new condom before anyone else uses them), and not sharing needles if you inject drugs.

Seek help from a sexual health clinic or your GP if you or a sexual partner has symptoms of syphilis, you've been told a partner has syphilis or an STI, you've recently had sex with a new partner and didn't use a condom, you're pregnant or planning to get pregnant and think you have syphilis, you've injected drugs using a needle that's been used with someone who might have syphilis.

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