A 10-month-old breast-feeding boy was taken to the emergency department (ED) with a temperature of 40°C (104°F). Because he was on day 7 of treatment with amoxicillin for a previously diagnosed ear infection, unresolved otitis media was diagnosed. Trimethoprim/sulfamethoxazole (TMP/SMX) was prescribed. However, the child’s fever persisted after 2 doses of TMP/SMX, and he was brought back to the ED the following day. He was given intramuscular ceftriaxone. The infant was seen by his primary care pediatrician for followup 2 days later. At that point, he was afebrile, but a few vesicles were visible on his tongue, anterior gingiva, and oropharynx.
Additional history revealed that a week earlier, the mother had had mastitis and was currently recovering from it; during the bout of mastitis, sores had developed on her lip. She also noted that within the past few days—around the time her son’s fever had developed—breast-feeding had become excruciatingly painful. Her nipples were examined, and crusting vesicles similar to those in the Figure were seen on her nipples; dried, healing vesicles were noted on her lip. The mother had a known history of recurrent oral herpetic lesions.
Samples for viral culture were obtained from the baby’s mouth and the mother’s nipple. The mother was advised to discontinue breast-feeding for 1 week and use a breast pump.
The infant’s culture results were positive for herpes simplex virus type 1 (HSV-1); the mother’s culture results were negative. Acyclovir was prescribed for the mother in an attempt to preserve the breast-feeding. The child and his mother were seen 1 week later. At that point, both were clear of vesicles, but the mother had discontinued breast-feeding because of pain; she also noted that she felt her milk had dried up, and she said her son was taking whole milk from a cup and "eating like a pig."
Breast-feeding is promoted by the American Academy of Pediatrics and other groups for many reasons. Benefits infants gain from breast-feeding include optimal nutrition; better bonding with their mother; enhancement of cognitive development; lower rates of diabetes, obesity, and sudden infant death syndrome; and especially, reduced rates of infection.1 Human milk contains an array of protective factors, including leukocytes, antibodies, lipids, and glycoconjugates, that provide resistance to infection.2
BREAST-FEEDING AND INFECTION TRANSMISSION
In some instances, however, breast-feeding can transmit infection. In this case, infection was transmitted from mother to infant— and then back to the mother via breast-feeding. Because this boy’s mother had a history of recurrent herpes labialis, it is reasonable to conclude that the infant contracted this infection from his mother. Although the results of a culture from the mother’s nipple lesions were negative, the clinical presentation and appearance of the lesions were consistent with a diagnosis of HSV infection. Thus, the most likely scenario in this case is that the mother infected the infant—probably by kissing him—and the infant subsequently infected the mother’s breast.
Transmission of HSV from mother to infant via breast-feeding.
There have been several reports of transmission of HSV to a newborn via breast-feeding. For example, Sullivan-Bolyai and colleagues3 report a case of disseminated HSV-1 infection in an infant, resulting in death at age 11 days, that was caused by suckling at a breast on which there was a nipple lesion that had appeared after birth. Cultures of specimens from the nipple lesion and lesions in the infant’s mouth were positive for HSV-1. The father had a history of HSV-1 infection, and he had had mouth-to-breast contact within 3 weeks of delivery. Quinn and Lofberg4 report the death of an 8-day-old infant from disseminated HSV infection that had developed shortly after lesions were noticed in the baby’s mouth. The infant had breast-fed for 4 days, and cultures of specimens from the mother’s vulva and cervix revealed HSV-2 infection.
Transmission of HSV from infant to mother via the breast.
There have only been 3 other mentions in the medical literature of the reverse type of transmission—of a child transmitting HSV to his or her mother via breast-feeding, as seen here. Sealander and Kerr5 report on a 15-monthold child who had acquired primary HSV-1 infection from his older brother and then infected his mother’s nipples when he breast-fed.
Dekio and colleagues6 describe a 10-month-old infant who transmitted HSV-1 to his mother. The authors do not report where the infant acquired the infection but note that he had a history of herpetic gingivostomatitis for 1 week before painful nipple lesions developed in the mother.
Gupta and colleagues7 describe a case of a 5-year-old boy and his mother, both of whom presented with painful vesicles; the vesicles first appeared in the child’s mouth and then developed on the mother’s left breast. Serology was positive for HSV-1 in both mother and child. The mother revealed that the child had a habit of sucking her nipples at bedtime.
THE TAKE-HOME POINTS
Transmission of HSV infection from an infant or child to its mother during breast-feeding—as occurred in this case—is rare. Sealander and Kerr5 speculate that such cases are uncommon because breast-feeding is generally discontinued in the United States before the age at which children usually acquire HSV-1 infection (2 to 4 years). They also note that the virus is not highly transmissible via breast-feeding. Still, it is important to ask the mother of a toddler or older infant with orolabial HSV whether she is breastfeeding, and if she is, to alert her to the associated risks.
Because transmission of HSV to the breast is rare, it would not be a contraindication to breast-feeding; if transmission did occur, the mother could be treated. However, in subsequent pregnancies, it is possible for a mother infected in this manner to transmit HSV infection to her new infant during breast-feeding, and she should be alerted to this risk.
A final note: herpetic nipple lesions may be very similar to the more common nipple erosions caused by trauma from poor latch. Because prompt diagnosis and treatment of HSV infection is so important in newborns, clinicians should maintain a high index of suspicion when examining vesicular lesions on a mother’s nipples during the neonatal period.