A case of acquired syphilis in an infant through mouth-to-mouth transmission of prechewed food.

Background: Patients with syphilis are the only source of infection, which can be transmitted through sexual contact and mother-to-child and blood transmission, and rarely through contaminants. The clinical manifestations of syphilis are complex and variable, and can be easily misdiagnosed. This article reports a case of syphilis in a child with "psoriasis"-like lesions who was fed pre-chewed food.

Case presentation: An 18-month-old girl presented with mung bean to peanut-sized erythema and papules scattered on both lower limbs and perianal area; some of the erythema was covered with scales, with clear boundaries and no fusion. The case was misdiagnosed as "psoriasis" in the local hospital until the child and her mother tested positive for syphilis in the outpatient clinic of our hospital. The girl's mother had a habit of chewing food in her mouth before feeding it to her child.

Conclusions: Consumption of food chewed by a person with syphilis can lead to infection, and attention should be paid to the possible ways and means of being infected.