The things that can cause nipple bleeding in a 4 month old male are usually less worrisome than those for an adult. The most likely culprit is irritation from clothing or other tight-fitting garments. Some babies will have a nipple discharge for a while after delivery as a result of maternal hormones, but this should be decreasing. I will list some things that should prompt immediate evaluation: fever, difficulty feeding, acting differently (less active or very irritable), bleeding, bruising, or purple-colored rash in other sites, continued bleeding or discharge. Is he otherwise well? How long has it been going on?
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