Syphilis is a bacterial infection that can affect many parts of the body, including the eye and eyelid. Caused by Treponema pallidum, it is primarily known as a sexually transmitted infection (STI), though it can also be passed from a pregnant person to their baby. While eyelid involvement is rare, it represents a notable manifestation of this complex disease.
Understanding Syphilis
Syphilis is caused by the bacterium Treponema pallidum and is typically transmitted through direct contact with a syphilis sore during vaginal, anal, or oral sex. It can also be passed from a pregnant individual to their fetus, leading to congenital syphilis. The infection progresses through distinct stages: primary, secondary, latent, and tertiary, each with varying symptoms.
The primary stage usually begins two to twelve weeks after exposure, marked by painless sores called chancres at the infection site. These sores often go unnoticed and typically heal within three to six weeks. The infection progresses to the secondary stage, which can develop one to six months after the chancre disappears. This stage often involves a rash that can cover the body, including the palms of the hands and soles of the feet, along with flu-like symptoms such as fatigue and fever.
Following the secondary stage, syphilis can enter a latent period, where the bacteria remain in the body without causing noticeable symptoms. This stage can last for years, with diagnosis often relying on blood tests. Without treatment, the infection may advance to the tertiary (late) stage, which can occur years after the initial infection. This stage can lead to severe complications affecting various organ systems, including the heart, brain, and eyes. Ocular involvement can occur at any stage of syphilis, but it is observed more commonly during the secondary stage.
Syphilis Manifestations in the Eyelid and Eye
Syphilis can affect various structures of the eye, presenting a wide range of clinical features. While rare, a primary syphilitic chancre can appear on the eyelid or conjunctiva due to direct contact with infectious secretions. These eyelid chancres typically present as firm, painless ulcerations. In the later tertiary stage of syphilis, more severe eyelid involvement can occur in the form of gummas, which are chronic, granulomatous lesions that can cause scarring upon healing.
Other Ocular Manifestations
Beyond the eyelid, syphilis can cause numerous other ocular manifestations:
Uveitis: An inflammation of the middle layer of the eye, which can affect the anterior, intermediate, or posterior parts of the uveal tract.
Keratitis: Inflammation of the cornea.
Retinitis and Chorioretinitis: Inflammation of the retina, or both the choroid and retina.
Optic Neuropathy: Damage to the optic nerve, leading to symptoms like blurred vision, flashing lights, or floaters, and can occur unilaterally or bilaterally.
Diagnosis and Treatment for Ocular Syphilis
Diagnosing syphilis, especially when ocular involvement is suspected, involves a combination of clinical examination and specific blood tests. Serological tests are broadly categorized into non-treponemal and treponemal tests. Non-treponemal tests, such as the Rapid Plasma Reagin (RPR) and Venereal Disease Research Laboratory (VDRL) tests, are used for screening and to monitor disease activity. These tests detect antibodies against lipoidal antigens released from damaged host cells.
If a non-treponemal test yields a positive result, it is typically followed by a treponemal test for confirmation. Treponemal tests, including the Fluorescent Treponemal Antibody Absorption (FTA-ABS) and Treponema pallidum Particle Agglutination (TP-PA) tests, detect antibodies specific to Treponema pallidum. These specific antibodies usually remain detectable for life, even after successful treatment. In cases of suspected neurosyphilis or ocular syphilis, a thorough eye examination is performed, and cerebrospinal fluid (CSF) analysis may be considered, although a lumbar puncture is no longer routinely recommended for ocular syphilis without neurological symptoms.
The standard treatment for syphilis, including ocular syphilis, is penicillin. For ocular syphilis, the recommended regimen is similar to that for neurosyphilis, typically involving intravenous aqueous crystalline penicillin G. This is administered at a dose of three to four million units every four hours, or as a continuous infusion of 18 to 24 million units per day, for a duration of 10 to 14 days. Penicillin is the preferred treatment because Treponema pallidum is highly sensitive to it, and it can effectively penetrate the central nervous system and eye. Alternative treatments, such as intramuscular penicillin G with oral probenecid or ceftriaxone, may be considered in certain situations, particularly for patients with penicillin allergies, though desensitization to penicillin is generally recommended.
Importance of Early Detection and Management
Prompt diagnosis and appropriate treatment of syphilis, particularly when it affects the eye, are paramount to prevent severe complications. Untreated ocular syphilis can lead to irreversible vision loss and even blindness. Early intervention can halt the progression of the disease and mitigate the risk of permanent damage to ocular structures.
The visual outcome for ocular syphilis is significantly better with early recognition and diagnosis. Delay in treatment can result in poorer outcomes, particularly if optic nerve involvement has led to optic atrophy. Early diagnosis and treatment also play a role in public health by preventing further transmission of the infection.