Intertriginous Rash in Secondary Syphilis

This clinical image report describes a 25-year-old woman with systemic lupus erythematosus (SLE) who presented with a 3-month history of erosive, violaceous plaques in intertriginous areas and scaly erythematous patches on the palms. She had been receiving hydroxychloroquine and prednisolone for SLE and reported condomless sex with one male partner. Serologic testing revealed a positive Treponema pallidum hemagglutination assay and an RPR titer of 1:128. Immunohistochemical staining of a skin biopsy confirmed T. pallidum. The diagnosis was secondary syphilis with atypical intertriginous rash, likely influenced by immunosuppression. Treatment with benzathine penicillin G led to resolution of the rash within one month and a decline in RPR titer to 1:16 at six months. The case underscores the variable presentation of secondary syphilis in immunocompromised patients and the importance of serologic testing and safe-sex counseling.

This clinical image report describes a 25-year-old woman with systemic lupus erythematosus (SLE) who presented with a 3-month history of erosive, violaceous plaques in intertriginous areas and scaly erythematous patches on the palms. She had been receiving hydroxychloroquine and prednisolone for SLE and reported condomless sex with one male partner. Serologic testing revealed a positive Treponema pallidum hemagglutination assay and an RPR titer of 1:128. Immunohistochemical staining of a skin biopsy confirmed T. pallidum. The diagnosis was secondary syphilis with atypical intertriginous rash, likely influenced by immunosuppression. Treatment with benzathine penicillin G led to resolution of the rash within one month and a decline in RPR titer to 1:16 at six months. The case underscores the variable presentation of secondary syphilis in immunocompromised patients and the importance of serologic testing and safe-sex counseling.