My 5-month-old gets lots of little pimples that come and go quickly. What causes them, and how can I prevent them?
Sounds like your child has miliaria -- also known as prickly heat or a heat rash. It's caused by blockage of the sweat ducts and is most common in newborns but can occur in older kids and adults, too. It happens in hot, humid weather, of course, but babies can get heat rashes even during the dead of winter from being bundled up tightly or snuggled close to their moms' breasts. When my youngest son, Liam, was an infant, he spent many of his older brother Zack's swim meets wrapped in a sling across my chest. After a few hours strapped to me at a hot pool, he nearly always had a few zitlike things on his face and neck.
The less you overbundle your baby, the less you'll see this rash -- but it's not dangerous and, as you said, goes away quickly, so there's really no treatment necessary. If the zits start to stick around, though, if the rash grows larger, or if your baby has a fever or seems very uncomfortable (miliaria can itch a little, but it shouldn't make babies very fussy), give your doctor a call.
Claire McCarthy, M.D., director of pediatrics at the Martha Eliot Health Center, in Jamaica Plain, MA, and a faculty member at Harvard Medical School. She's also busy raising five children.