A 22-year-old man presented with a 2-week history of non-pruritic symmetric erythematous rash on his palms and soles. On examination, there was no associated fever, lethargy, arthralgia or lymphadenopathy. Physical examination revealed multiple erythematous macules with an off-white scaly peripheral collarette, consistent with Biett’s sign (Figure 1A and B). There was also a well-circumscribed, painless, solitary, indurated genital ulceration, which was noticed 20 days ago. The patient disclosed engaging in unprotected sexual activity with male partners. He had been treated for a suspected fungal infection with terbinafine cream for 2 weeks, but the lesions did not improve. A clinical diagnosis of secondary syphilis was made, confirmed by a positive Treponema pallidum hemagglutination assay and a Rapid Plasma Reagin titer of 1:128; the serological result for human immunodeficiency virus was negative. The patient was therefore treated with oral prednisone (30 mg/day for 3 days) and intramuscular penicillin G benzathine at 2.4 million units once a week for 3 weeks. At his 1-month follow-up, the patient had complete clinical resolution.
Multiple erythematous, well-demarcated macules covered with marginal collarette scales on the palms (A) and soles (B).
Syphilis, experiencing a high prevalence or a resurgence in many countries and territories worldwide, is distinguished by its multistage course of disease.1 Without effective intervention, clinical features unfold, including a primary chancre at the site of inoculation, the rash of secondary syphilis, a latent period, and in certain cases, the involvement of CNS, the eyes and cardiovascular systems.2 Syphilis is diagnosed serologically. But the multiple and atypical manifestations of syphilis, especially in the secondary stage, may result in misdiagnosis and delayed treatment. There is a need for increased willingness to consider the diagnosis of syphilis in patients with vague lesions. Biett’s sign, first described by Laurent-Théodore Biett, refers to the peripheral scaling around an individual secondary syphilis rash.3 Dermoscopy helps to rule out differential diagnosis with findings of diffuse monomorphic dotted and glomerular vessels on an erythematous, copper-colored background, accompanied by a circular scaling edge.4 This hallmark sign has proven to be a robust indicator for accurate and early diagnosis of secondary syphilis.
Author contributions
Y.Z. collected the clinical data and wrote the manuscript. M.X. provided care for the patient and revised the article.
Funding
There is no funding.
Conflict of interest
None declared.
Data availability
Data are available on request from the authors.
