Syphilis in children is hard to imagine because children are rarely sexually active, but infection does occur either due to vertical transmission during pregnancy or delivery (congenital syphilis) or in ways similar to those of adults (acquired syphilis). Previous literature has described acquired syphilis in children almost exclusively as from sexual transmission from sexual abuse by an infected adult.1,2 However, children may also acquire syphilis as a consequence of close contact, such as kissing, breast-feeding, fondling, handling, or prechewed food feeding, or even use of contaminated utensils, when family members or caregivers are affected by active syphilis.3 – 8 Here, we report 3 cases from China, where syphilis is heavily endemic.
Patient A is a 5-year-old boy who presented with erythematous eruptions over his body for 2 months. He had been well until 2 months ago, when he had a sore throat and oral mucosal lesions. Then, he developed a mildly pruritic rash on his neck, which gradually spread to his extremities and trunk. The child's condition was initially diagnosed and treated as psoriasis vulgaris by his primary care physician 1 month prior, but the lesions continued to worsen. Finally, he was referred to us for further evaluation. Physical examination at the time of referral revealed hyperemia of tonsils and pharynx, and numerous oval red-brown patches with peripheral scales, 1 to 5 cm in diameter, which were scattered on the trunk and concentrated on the palms and soles (Fig. 1A). There was also an irregular maplike erythematous plaque, 3.5 cm in diameter, and numerous small red papules over his tongue (Fig. 1B). He had bilateral submandibular and retroauricular lymphadenopathy. There were no anogenital lesions or injuries identified, and his scalp and hair were normal. The neurologic examination and psychiatric evaluations showed no abnormalities. Serological tests showed positive rapid plasma reagin (RPR) at a titer of 1:128, and positive results of Treponema pallidum particle agglutination assay (TPPA) and negative results of human immunodeficiency virus (HIV) test. After consideration of the clinical findings and laboratory data, secondary syphilis was diagnosed.
The diagnosis was surprising for the child's parents. Both the parents denied a history of syphilis and any symptoms of syphilis. The mother's routine prenatal RPR and HIV tests had been negative, and the child was also normal at birth. Both the mother and father had another serology examination, including RPR, TPPA, and HIV, and the results were negative again. Then, the child was interviewed alone by our medical team, but the boy denied the sexual assault. Because the child lived with his grandmother (57 years old), who was his primary caregiver, and his grandfather (59 years old), the grandparents were asked to come to the hospital to provide further information. Both the grandparents denied a history of syphilis, high-risk behaviors, or symptoms. The physical examinations of the grandparents showed no oral lesions and other signs of syphilis infection. However, the results of their serological tests showed positive RPR (1:64), positive TPPA, and negative HIV. On further inquiry, the grandfather admitted to extramarital unprotected sexual intercourse 5 months prior, while continuing to have sex with his wife. Both the grandparents were diagnosed with early latent syphilis. All of the family members denied the possibility of sexual abuse or assault of the child. The socioeconomic status of this family is very good. The boy was primarily looked after by his grandmother, who said that she protected the boy carefully and regularly kept the child with her everywhere. Thus, sexual assault of the boy seemed impossible. Treatment with 3 successive weekly doses of 50,000 IU/kg intramuscular penicillin G benzathine (Bicillin) was completed. All of the lesions were resolved within 30 days of treatment initiation, and the results of follow-up serologic tests showed lower reagin titers (1:8) at the 90th day after treatment completion.
Patient B is a 3-year-old girl who was referred to our hospital for evaluation and treatment of syphilis. She had been well until 10 days prior when a rash appeared first on her palms and then on her soles. Before she visited us, she had a positive serological examination for syphilis with an RPR of 1:8 and positive TPPA. Her HIV test was negative. The girl did not feel any discomfort before visiting us. Physical examination showed erythematous patches on her palms and soles, which were similar to those in patient A but fewer in number. There were no lesions in her mouth, and lymphadenopathy was not observed. On examination, the anogenital region was normal, and no injuries were found. The hymen was intact without scarring, and no vaginal discharge was discovered. In addition, the neurologic examination and psychiatric evaluations were normal. The diagnosis of secondary syphilis was definitive. The child was interviewed alone by us, and she denied any violence including sexual assault. The girl came from a middle-class family. All of the family members denied a history of syphilis and sexual abuse of the girl. Family members all underwent serological examination, and the results revealed that the girl's 26-year-old aunt and caretaker had positive RPR (1:32) and TPPA with a negative HIV test. The rest of the family members including the child's parents had normal results. On further inquiry, the child's aunt admitted that she had unprotected sex about 2 months prior with her boy friend but had no symptoms after that incident. Her physical examination showed no signs of syphilis, including oral lesions. Thus, she was diagnosed with early latent syphilis. The treatment for the girl was the same as that of patient A. The patient is still being followed up.
Patient C, a 4-year-old girl, visited us with her mother. The mother said that she had found a rash around the girl's anus for more than 1 month. At first, there was only one 0.5-cm sized nonpruritic, nonpainful flat papule in the perianal area. Then, the lesion increased in number and size rapidly. Physical examination showed several hypertrophic, flat-topped, moist verrucous plaques, which felt tender around the anus. These plaques were 1 to 2 cm in diameter, superficially ulcerated, and had an unpleasant odor. Genital examination revealed no injuries with the hymen being intact, and no vaginal discharge was discovered. There were no other lesions in the trunk and limbs, no scalp and hair abnormalities, and also no oral lesions. The neurologic examination and psychiatric evaluations were normal. Because the clinical feature of anal lesions was consistent with condyloma latum, the girl was at risk for syphilis and asked to take serological tests for syphilis and HIV. The results showed positive RPR at a titer of 1:64, positive TPPA, and negative HIV. A scraping smear examination under a darkfield microscope demonstrated multiple spirochetes, thereby confirming the diagnosis of secondary syphilis. All of the patient's family members were asked to undergo serological exams. The results were extremely similar to those of patient A. The parents tested negative. The girl lived with her maternal grandparents who had proven early latent syphilis without any symptoms but with the positive RPR (1:32) and reactive TPPA. The child's 60-year-old maternal grandfather admitted to having unprotected sex with a prostitute about 4 months prior while still having sex with his 55-year-old wife who acted as the girl's caregiver. The girl was interviewed alone by us, and she denied any sexual assault. The girl came from a middle-class family. All of the family members denied sexual abuse of the child. The girl received the same treatment as the previous 2 patients. The anal lesions had been resolved by the patient's second visit 30 days after the treatment initiation; however, the patient was lost to follow-up after that.
These 3 cases were very similar in many aspects. For example, the children were all infected with secondary syphilis via transmission from caregivers with early latent syphilis, without a background of sexual abuse. We know that syphilis in children may be acquired or congenital, and a significant increase in congenital syphilis in children has been reported in recent years in China.9 In 2010, a total of 12,166 cases of congenital syphilis in China were reported.10 Comparatively, there have been fewer reported cases of acquired syphilis in children. Although acquired syphilis in children is infrequent, it should not be ignored. When primary or secondary syphilis occurs in children, sexual transmission must be considered, and sexual abuse is the most common mode of transmission.11,12 However, other forms of transmission are possible. In a report of 125 cases of acquired syphilis in patients aged 10 years or younger, 34% were due to sexual abuse, whereas 23% were reportedly due to innocent kissing or household contact.13
When referring to nonsexual syphilis transmission, Hudson stated an interesting history of the origin of syphilis. He said that treponemal infection of man originated in tropical Africa in Paleolithic times by nonvenereal contagious contact and subsequently evolved to be almost entirely sexually transmitted with the environmental change.14 Also, some previous reports declare that acquired syphilis in children often happened in poor environmental conditions, but Murrell and Gray state that some infections occurred in professional families.4 Take our cases, all 3 children came from a middle or upper class family and received a considerable amount of care. Additionally, some research revealed that T. pallidum can be present in the oral cavity and may be transmitted to individuals through close contact with the host.15 An infectious mother or caregiver is of particular risk to the infant due to the common practices of using saliva to moisten teats of feeding bottles and dummies and to test the temperature of food by tasting from the infant's spoon. Furthermore, infants and young children often thrust their fingers into their mother's mouth and then into their own.16 Recently, it was reported that infants can contract syphilis by mouth-to-mouth transfer of prechewed food from actively infected relatives.6 However, this mode does not exist in our cases. This behavior is most commonly observed in infants before teething, usually before the age of 1 to 2 years, and often happens among people from rural areas or who are poorly educated.6,15 Usually, it is very difficult to detect the specific routes leading to infection; therefore, we used a general term of “close contact.” In our cases, the children lived with their caregivers, possibly sharing contaminated beds, towels, lavatories, and eating utensils. Other close contact behaviors also existed, such as kissing, fondling, helping with baths, and so on. It was suggested that the intimate relationship within the family, especially between the mother or caregiver and the child, made the nonsexual transmission of syphilis not an unlikely occurrence.16
Because much concern is focused on congenital syphilis, acquired syphilis in children has received relatively little attention. Smith stressed that no true evaluation of the incidence can be obtained from the group.13 Our cases support the suggestion that acquired syphilis in children is more common than was generally supposed, and domestic close contact could be a means of disease transmission that has not been fully recognized. However, although we found no evidence of sexual transmission, we acknowledge that one can never fully exclude the possible sexual transmission in our cases. Although we report nonsexual close contact as a possible mode of syphilis transmission in children, we intend to strengthen the opinion that it is essential to consider nonsexual transmission only after all investigations into possible sexual abuse have been made. Early recognition of acquired syphilis in children is important for the prevention of transmission to other children and the development of cardiovascular and neurologic signs by adequate treatment. However, preventing syphilis infection in children can be challenging due to the high incidence of syphilis infection in adults in China, and covert syphilis transmission may occur because of 52% of syphilis cases being latent syphilis.10 We suggest that routine examination and follow-up of familial contacts of patients with early infectious syphilis should be carried out, and further epidemiologic investigation should be conducted.
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