Syphilitic chancre of the lower lipLingyi Zhao1Yao Ni1,3Jingying Sun1Janzhou Ye2*Department of Dermatovenereology, Chengdu Second People’s Hospital, Chengdu, ChinaDepartment of Dermatovenereology, Yunnan Provincial Hospital of Traditional Chinese Medicine, Kunming, ChinaDepartment of Dermatovenereology, Nanjing University of Traditional Chinese Medicine, Nanjing, China* Corresponding Author: [email protected] head: Syphilitic chancre of the lower lipThe category of the article: LetterKeywords: Syphilitic chancre, lower lipManuscript word count: 679 wordsThe number of figures: 2The number of tables: 0The number of references: 7Correspondence to: Janzhou Ye, M.D, Ph.D., Department of Dermatovenereology, Yunnan Provincial Hospital of Traditional Chinese Medicine, Kunming, 650021, China.Tel: +86 13908710661; E-mail: [email protected] conflict of interest statement: Lingyi Zhao, and my co-authors have no conflict of interest to declare.Ethics statement: The patient has consented to publish this information.Data availability statement:Data sharing does not apply to this article as no new data were created or analyzed in this study.Funding sources: noneDear Editor,Syphilis is a chronic infectious disease usually caused by spirochete Treponema pallidum. Nowadays, it is estimated that there are more than 11 million new cases of syphilis in the world every year, and more than 90% of the cases are in developing countries1. Syphilis re-emerges mainly in men who have sex with men（MSM）in high-income countries. In contrast, it is an endemic disease in low-income countries. Although its mortality rate decreases, its varied clinical manifestations are likely to lead to misdiagnosis or delayed diagnosis, especially when the primary lesions occur in the extragenital regions. Treponema pallidum usually enters the human body through microlesions in the skin or mucous membrane. The typical primary painless ulcerative lesion, which is called a chancre, often develops at the site of inoculation within 10 to 90 days after unprotected sexual intercourse.Here we report a 26-year-old man presented to the dermatology department with a painless ulcer on the midline of his lower lip for 3 weeks (Fig. 1). The isosceles triangular ulcer is measured 1.3cm in waist length, 0.7cm in base length with a smooth, clean base and indurated, elevated borders, which was slightly bleeding. The patient announced not any other lesion on his trunk or limbs. He initially visited a clinic and was prescribed mupirocin ointment. He used the ointment for a week and went to another clinic due to no significant improvement of the ulcer. This time he applied acyclovir cream. After two weeks, the ulcer had not improved. The patient claimed to have had unprotected orogenital sex with two women in two months. He declared he had not any prior sexually transmitted infection. Physical examination showed no remarkable signs on the trunk, limbs, especially genitals or anus. Peripheral lymphadenopathy was not revealed clearly. Toluidine red unheated serum testing was positive with a titer of 1:16, in the meantime treponema pallidum particle agglutination assay was positive. He tested negative for human immunodeficiency virus. The situation of those women was unclear because he had been out of touch with them. The patient was treated with benzathine penicillin (2.4 million) once a week for 3 consecutive weeks. The lesion was undetectable completely after 4 weeks (Fig. 2).