The last time I blogged about this sexually transmitted disease was in 2018 when UK cases reached nearly 6000 that year. Well, for those of you following the news, you will have no doubt seen that case numbers have continued to rise to 8692 in 2022 (Click Here)
That’s the highest level in 75 years. The data suggests this is mainly in the 15–24-year-old age group. It is important to remind podiatrists that syphilis is often a difficult diagnosis to make due to its highly variable presentation, but the feet may hold some strong clues. For further reading I recommend the paper (1) below which is free to download from the publisher’s website, on which this blog is based.
The disease is caused by a spirochete Treponema pallidum which is passed through small skin or mucosal injuries. The infection, once in the body can spread and multiple in the bloodstream and lymphatics. Most infections arise through sexual contact, but it can be passed congenitally or rarely through infected blood products. The condition can potentially progress through three stages and have active and latent phases.
Syphilis presenting on the soles as a macular rash with hyperkeratotic edge
(Image from Sadoghi et al., under creative common licence)
In the primary stage infection occurs and there is usually a painless ulcer develops at the point of contact up to 90 days following exposure to the infection. Local lymphadenopathy may also be present. Serological testing in the early stages may not always be conclusive. Spontaneous resolution of the initial ulcer within a few weeks is possible.
Syphilis presenting on the palms as a macular rash with hyperkeratotic edge
(Image from Sadoghi et al., under creative common licence)
After around 10 weeks around a third of patients enter the second stage. This stage can last for up to 2 years. Moreover, two thirds of patients are diagnosed at this phase of the disease. Although there is a diversity in the potential symptoms at this stage, localised papules frequently appear on the palms and soles. Itching is an unusual feature. Lesions typically are targetoid macules or plaques (2) (see above) and may have a surrounding white scale. These are known as “syphilitic clavi”. They are typically between 0.5cms – 2cm in diameter with coppery red-brown hue. Differential diagnosis with psoriasis is important through serological testing for the infection. The macular rash may be present over the whole body. It is important to remember that the rash is variable and may take on alternative appearances such as pustular, nodular or lichenoid (3). Other symptoms of syphilis include:
Other more generalised signs and symptoms associated with secondary syphilis include (5):
· Mucosal lesions
· Weight loss and fever/malaise
· Hair loss (patchy “moth eaten” or thinning). Can affect the eyebrows and beard areas.
· Paronychia
· Lymphadenopathy (generalised with painless lymph nodes)
· Neurological symptoms / headaches / meningitis
· Eye problems
· Glomerular nephritis
· Joint swelling / arthritis
· Hepatitis
· Myocarditis
Where the syphilis is suspected patients should be referred to their local sexual health clinic where testing and treatment for the disease can be undertaken.
References:
1. Sadoghi B, Stary G, Wolf P. Syphilis. JDDG: Journal der Deutschen Dermatologischen Gesellschaft. 2023;21(5):504-17. Full Paper download – click here
2. Moreira C, Pedrosa AF, Lisboa C, Azevedo F. Clavi syphilitici–an unusual presentation of syphilis. J Am Acad Dermatol. 2014;70(6):e131-e2.
3. Whiting C, Schwartzman G, Khachemoune A. Syphilis in Dermatology: Recognition and Management. Am J Clin Dermatol. 2023;24(2):287-97.