Syphilis overview

Syphilis is an STD caused by the bacterium Treponema pallidum. It can affect individuals of all ages. However, it mostly affects those that have unprotected sex or risky sexual behaviors. Syphilis has four stages. It is a genital ulcerative disease that may lead to death if left untreated. Those that should get regular screenings for the disease are men who have sex with men (MSM), sex workers, pregnant women, people with HIV, and individuals whose partners have syphilis. Congenital syphilis is also an issue, transmitted from a mother to her child. Researchers are always pointing out the need to stop syphilis spread and practice safe and responsible sex.

The stages of syphilis

The first stage signals the commencement of the infection. It starts with a small, round, painless sore. You may observe it anywhere in your body, but especially in or around your genitals, anal area, or mouth. The sore or chancre represents the entry point of the infection. The secondary stage of syphilis appears in those that fail to recognize and treat the disease during its primary phase. It includes rash that may appear on the skin, mouth, genitals, or anus. Constitutional symptoms may commence, as well. The latent syphilis stage may be asymptomatic. Finally, after ten to thirty years since the appearance of the first syphilitic sore, syphilis may progress into the tertiary stage. It is a life-threatening condition that may also lead to neurosyphilis. 

When does syphilis rash appear?

Syphilis rash appears during the secondary stage of syphilis and after the disappearance of the primary sore. It appears around three weeks after the initial sexual contact, accountable for the infection. The sores are painless, firm, and round. However, the rash is only a symptom of this phase. Most people will also have constitutional signs, such as fever. It is not itchy and may start from the trunk, eventually involving the entire body, including the palms and soles. The rash will appear as brown/red spots on the skin. Most of the time, rashes on the palms and soles suggests secondary syphilis. An estimated 20% of adults will also have mucous patches and condylomata lata. These lesions are flatter than condylomata aluminate. Moth-eaten alopecia can occur in some individuals too. 

How does a syphilis rash look?

A syphilitic rash appears as discolored, non-itchy patches, called macules. The discoloration will give them a brown or red aspect. Their primary site is the trunk, and eventually, they extend to the entire body, including the palms and soles. This type of rash is highly suggestive of syphilis. Although most of the time, syphilitic patches are flat, someone might observe elevated ones, as well. Generally, secondary syphilis might present with some of the following:

  • skin manifestations in 90% of the cases
  • oral lesions in 35% of the cases
  • genital lesions in 20% of the cases
  • constitutional symptoms, such as fatigue, malaise, and fever in 70% of the cases

There is also a variant of secondary syphilis called malignant syphilis. In this case, the rash has a fast progression with a tendency towards ulceration. Various layers of thick crusts cover it, and the patient may also experience toxemia and hepatitis. Therefore, syphilis is a disease with high variability, making it hard and challenging to diagnose.  

What else could it be?

Due to its high variability regarding its clinical course, secondary syphilis may mimic other skin conditions as well. To differentiate between the potential causes of the rash, physicians suggest testing to exclude or confirm syphilis. Doctors refer to it as the great mimicker, due to its wide range of clinical manifestations. Even the syphilitic rash does not look the same in every individual. While some people may present with flat patches, others may have elevated lesions, called papules, or even signs of malignant syphilis. The most common differential diagnoses are Pityriasis rosea and viral exanthem. 

Pityriasis rosea

Pityriasis rosea is a skin condition that manifests itself with a circular or oval patch on the trunk, abdomen, or back, called herald patch. Meanwhile, the rash extends to the other parts of the body as smaller spots. In contrast with syphilitic dermatitis, pityriasis rosea is itchy. However, it also appears in the presence of constitutional symptoms, such as malaise, headache, or fever. 

Viral exanthem

Viral exanthem is a skin condition that presents secondary to a virus. It is a symptom that may appear secondary to some adenoviruses, enteroviruses, measles, and other types of viruses. Some types of herpes infection may also cause exanthem. It is a highly contagious condition, and people with it should avoid contact with others. Those with a viral exanthem might experience constitutional symptoms as well, such as malaise, fatigue, fever, and sore throat. 

What should you do if you have such a rash?

If you experience any of the symptoms and signs of syphilis, you should get tested for it as soon as possible. Keep in mind that the disease can mimic various other diseases and infections due to its high clinical variability. Getting tested at home with an STD test kit is a simple and accurate procedure that can provide you with results in less than twenty minutes. Testing for syphilis is possible from ten days after exposure. In case you are positive for syphilis, you should get tested again after you complete the course of your treatment. 

Is syphilis curable?

The disease is treatable, and the results are better once identified early. Having a rash means you are on the second stage of syphilis, which is still manageable. If left untreated, syphilis may lead to life-threatening complications. Keep in mind that the syphilitic rash goes away on its own. What follows is the latent phase, which is asymptomatic. Many people ignore the fact they have a rash, just because it disappears without treatment. However, once it disappears, you are one step away from tertiary syphilis, a stage in which the bacterium invades other organs in your body, leading to organ failure and death. 

To avoid syphilis and its deadly complications, screen yourself regularly and avoid reckless sexual behaviors. Make sure you use protection every time you engage yourself in sexual activities, especially with people you don't know well.

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Syphilis Rash