Secondary Syphilis in a 21-Year-Old Woman With Diffuse Mucocutaneous Lesions: A Case Report and Diagnostic Review.

This case report describes a 21-year-old woman who presented with diffuse, non-pruritic erythematous papules involving the palms, soles, cervical region, inguinal folds, and perineal area. The lesions appeared approximately one month following unprotected sexual contact with a partner with multiple previous sexual relationships. Clinical examination revealed well-demarcated, lenticular papules with fine scaling and generalized non-tender lymphadenopathy, without mucosal erosions or genital ulcers. Serologic testing confirmed the diagnosis of secondary syphilis, with high titers on both treponemal and non-treponemal assays. The patient was treated with a single intramuscular injection of benzathine penicillin G and supportive therapy. Early clinical improvement was observed, and follow-up serological monitoring was arranged. This case emphasizes the importance of recognizing the protean manifestations of secondary syphilis, which may mimic other dermatologic or systemic conditions. Prompt diagnosis through comprehensive history-taking, physical examination, and appropriate serological testing is critical. In addition to treatment, counseling and partner notification are essential components of management to prevent reinfection and curb disease transmission. This report highlights the continued relevance of syphilis in modern clinical practice and underscores the importance of maintaining a high index of suspicion, particularly in young, sexually active individuals presenting with unexplained mucocutaneous lesions.