A barely visible or invisible painful crack on the nipple might be herpes simplex virus

Occasionally, a barely visible or invisible painful crack on the nipple can be herpes simplex virus (HSV). Herpes on the nipple or breast may be a tiny vesicle or blister on an inflamed, red base. This blister breaks down into an ulcer, which sheds virus, and may be surrounded by a rim of somewhat swollen, angry red skin.

Sometimes, herpes of the nipple and areolar complex or breast might appear as a painful cluster of vesicles on slightly swollen red bases. This tends to occur when you are having your first, or primary, outbreak of herpes. There may also be tender lumps in your axilla, which are your lymph nodes reacting and doing their job of managing the infection.

Newborns can die from a herpes virus infection. Under three months of age, babies lives can be threatened by a herpes virus infection and related central nervous system involvement. This is why it is very important that your baby and most particularly your newborn never come into contact with an active lesion. If you have a cold sore on the mouth, it’s very important that you don't kiss your baby until it’s completely healed.

Almost all adults have been exposed to herpes simplex virus type 1 (HSV 1), usually acquired in childhood and carried throughout life. HSV 1 is the most common cause of ‘cold sores’, though sometimes HSV 2 can cause them. Some of us are immune to HSV 1, but others will have active outbreaks of cold sores on the lips, or as small blisters in the mouth life-long.

Genital herpes is most often HSV 2 but can also sometimes be HSV 1, and occurs in 1 in 5 women.

What should you do if you’re worried you have a herpes simplex virus infection of the nipple or breast?

If you think you are at risk of a herpes infection on the nipple or breast, for example because you have pain there and you or your partner or other family member have had a herpes outbreak, keep that breast covered and away from your baby until you’ve seen your GP.

Your doctor will take a polymerase chain reaction (PCR) swab and discuss next steps with you. If you are both concerned, your doctor will commence an antiviral medications for 5-7 days, which is safe to use while breastfeeding, and which hastens the healing and decreases viral shedding from the sore.

You can continue breastfeeding if you have a cold sore or herpes lesion of your vagina or vulva, but needless to say the sores need to be covered and never in contact with the baby.

If you have a sore on the nipple, areola or breast, it’s very important not to feed from that side. Similarly, if milk can be expressed without your hand or pump coming into contact with the lesions, and if it is an older baby, that’s might be ok. Sometimes, in an older baby, and if the sore is not on the nipple and areola and can be covered, you might discuss with your doctor if it is safe to breastfeed. You’ll need to discard pumped milk from that breast, and to make sure that the sores are thoroughly covered when you breastfeed from the other side. Milk from the affected side needs, sadly, to be dumped. You need to carefully wash your hands with soap before handling the baby, and sterilise pump parts thoroughly after use.

Your doctor will also talk with you about how to know when the lesion is healed and when it is safe to recommence breastfeeding. You'd wait until the skin has reformed over the break, which takes perhaps a week. It is safest to err on the side of caution, especially if you have a newborn, and for this reason it’s important to be under the care of your local GP.

If your breastfeeding toddler develops a cold sore, you’ve already been exposed (if the little one didn’t catch it from you anyway!) because HSV is contagious for one to three days before lesions appear. Toddlers may experience their first herpes outbreak as a herpes stomatitis, that is, an outbreak of sores in the mouth. This again should be checked out by your local doctor. Occasionally a woman will develop a primary herpes infection on her breast, which is always more severe and usually with multiple lesions, perhaps because her toddler has given it to her. The risk of HSV transmission by breast milk is low.

What should you do if you have a varicella zoster (chickenpox or shingles) infection?

A rash caused by varicella zoster, which is part of the herpes family, can also present as a cluster of painful vesicles across your chest and breast. This outbreak is known as shingles. It is a re-activation of the virus that caused you to have chickenpox earlier in your life, and which lives on in nerve nodes. Shingles is typically very painful and the lesions are spread across a whole long strip of skin on your torso.

A varicella zoster outbreak on an adult can infect an unimmunised child and result in that little one coming down with chickenpox. Again, in a newborn, varicella zoster infection can be fatal. In the case of this particular kind of herpes infection, the mother is immune and it is important to keep breastfeeding rather than wean onto commercial milk formula, as baby will be receiving antibodies through her milk.

The exception is if the outbreak of shingles occurs within five days before or in the two days after birth. In this case, the baby will require treatment with zoster immune globulin, because of the danger of fatal herpes zoster infection. It is important that you see your doctor, who will commence you on acyclovir, as with herpes simplex virus infection.

Selected references

Quinn PT, Lofberg JV. Maternal herpetic breast infection: another hazard of neonatal herpes simplex. Medical Journal of Australia. 1978;2(9):411-412.

Gupta S, Malhotra AK, Dash SS. Child to mother transmission of herpes simplex virus-1 infection at an unusual site. Journal of European Academy of Dermatology and Venereology. 2008;22(7):878-879.

James SH, Whitley RJ. Treatment of herpes simplex virus infections in pediatric patients: current status and future needs. Clinical Pharmacology and Therapeutics. 2010.

Barrett ME, Heller MM, Stone HF, Murase JE. Dermatoses of the breast in lactation. Dermatologic Therapy. 2013;26:331-336.

Barrett ME, Heller MM, Fullerton H, Murase JE. Primary Herpes Simplex Virus infection of the nipple in a breastfeeding woman 2016.

Dekio S, Kawasaki Y, Jidoi J. Herpes simplex on nipples inoculated from herpetic gingivostomatitis of a baby. Clin Exp Dermatol. 1986;11(664-666).