Syphilis in Singapore: Stages, Symptoms, Testing, and Treatment

The Four Stages of Syphilis

Syphilis progresses through distinct stages. Understanding each stage helps explain why the infection is so often missed and why early testing matters. 

Primary Stage (2 to 6 Weeks After Exposure) 

The first symptom is a sore called a chancre. It appears at the site where the bacteria entered the body, typically on the penis, vagina, anus, rectum, lips, or inside the mouth. The chancre is firm, round, and characteristically painless, which is precisely why it is so frequently overlooked. 

Chancres located inside the vagina, rectum, or throat are often invisible to the infected person. Even visible chancres are commonly mistaken for a minor skin irritation or ingrown hair. The sore heals on its own within three to six weeks, regardless of whether treatment is given, which reinforces the false impression that the problem has resolved. 

Without treatment, the bacteria have already entered the bloodstream. 

Secondary Stage (Weeks to Months After Primary) 

If untreated, syphilis progresses to the secondary stage, characterised by a rash that often appears on the palms of the hands and soles of the feet, a distribution that is unusual for most skin conditions and is a classic clinical clue. The rash may also appear on other parts of the body. 

Other symptoms during the secondary stage may include fever, swollen lymph nodes, sore throat, patchy hair loss, headaches, unexplained weight loss, muscle aches, and persistent fatigue. 

These symptoms are non-specific and are frequently misdiagnosed as a viral illness, allergic reaction, or other common condition. Like the primary chancre, secondary symptoms resolve on their own without treatment, typically within a few weeks to months. The infection, however, continues to progress. 

Latent Stage (Years to Decades) 

After the secondary stage resolves, syphilis enters its latent phase. During this stage, there are no visible signs or symptoms whatsoever. The infected person feels completely well and has no reason to suspect they carry the infection. 

As we discussed in our blog on STDs that can lie dormant for years, latent syphilis can persist for years or decades. During early latent syphilis (the first one to two years), sexual transmission is still possible. During late latent syphilis, transmission risk decreases but the bacteria remain in the body, capable of progressing to the most dangerous stage. 

The latent phase is where the majority of undiagnosed syphilis cases sit: people who were infected years ago, whose symptoms resolved spontaneously, and who have no idea they carry the bacteria. 

Tertiary Stage (Years to Decades After Initial Infection) 

In approximately 15 to 30 per cent of untreated cases, syphilis progresses to the tertiary stage, which can cause severe, potentially life-threatening damage. 

• Cardiovascular syphilis - Damage to the aorta and heart valves, potentially causing aortic aneurysm, aortitis, and heart failure. 
• Neurosyphilis - Invasion of the brain and nervous system, causing severe headaches, muscle weakness, difficulty with movement, personality changes, confusion, memory problems, dementia, and, in advanced cases, paralysis. 
• Gummatous syphilis - Destructive soft growths (gummas) that develop on the skin, bones, liver, or other internal organs, causing tissue damage and organ dysfunction. 
• Ocular syphilis - Inflammation of the eye leading to eye pain, redness, vision changes, and potentially blindness. This can occur at any stage, not just tertiary. 
• Otosyphilis - Affects the ear, causing hearing loss, tinnitus, and vertigo. Like ocular syphilis, this can occur at any stage. 

All tertiary complications are preventable through early detection and treatment. The damage caused by tertiary syphilis is often irreversible, making early testing the critical intervention.