Baby acne is caused primarily by hormonal activity that stimulates oil production in a newborn’s skin. It affects about 20% of infants under six weeks old, making it one of the most common skin conditions in newborns. The bumps typically appear on the cheeks and can look alarming, but they’re almost always harmless and temporary.
How Hormones Trigger Baby Acne
The main driver behind baby acne is a high rate of oil (sebum) production in newborn skin. During the final weeks of pregnancy, maternal hormones cross the placenta and enter the baby’s bloodstream. These hormones, particularly androgens, stimulate the baby’s sebaceous glands to produce far more oil than the skin actually needs. That excess oil clogs tiny pores, leading to the small bumps and pimples parents notice in the first few weeks of life.
In boys, both the adrenal glands and testes contribute to androgen levels after birth. In girls, the adrenal glands are the primary source. This hormonal surge is completely normal and settles on its own as the baby’s body clears the circulating hormones over the first few months.
The Yeast Theory Has Been Mostly Ruled Out
For years, some dermatologists suspected that a common skin yeast called Malassezia played a role in baby acne. A study of 104 neonates tested this theory by sampling the cheeks and scalps of newborns within 72 hours of birth and again at two to four weeks. Yeast colonization did increase with age, from about 5% in the first week to 30% by the second to fourth week. But colonization rates in babies with pustules were actually lower (about 21%) than in healthy newborns (37%), and there was no correlation between the severity of the rash and the presence of yeast. So while Malassezia lives on many babies’ skin, it doesn’t appear to cause or worsen baby acne.
What Baby Acne Looks Like
Baby acne most commonly appears on the cheeks, though it can also show up on the forehead, chin, scalp, neck, upper back, and upper chest. The bumps range from tiny whiteheads and blackheads to small red or inflamed pimples. In some cases, slightly larger raised bumps (papules or pustules) develop. The skin around the bumps may look mildly red, especially after crying or when the baby is warm.
The rash usually appears within the first two to four weeks of life. Most cases are mild, with scattered bumps across the cheeks that come and go over several weeks before fading entirely.
Baby Acne vs. Other Newborn Rashes
Several newborn skin conditions can look similar at first glance, and telling them apart helps you decide whether to leave things alone or bring it up with your pediatrician.
- Milia are tiny white cysts just under the surface of the skin, caused by trapped keratin (a skin protein). They’re sometimes called milk spots. Unlike baby acne, milia aren’t red or inflamed. They look like pinpoint white dots, usually across the nose, cheeks, and chin, and they resolve on their own without any redness or swelling.
- Eczema (atopic dermatitis) produces dry, scaly, and inflamed patches rather than individual pimples. In babies under six months, eczema typically appears on the face, cheeks, chin, forehead, and scalp. The key difference is texture: eczema skin feels rough, dry, or crusty, and it tends to itch. Baby acne produces distinct bumps (whiteheads, blackheads, small pimples) on otherwise normal-feeling skin. If the skin looks red and weepy or develops a yellow crust, that points more toward eczema, possibly with a secondary infection.
- Heat rash shows up as tiny, clear or red bumps in areas where sweat gets trapped, like skin folds, the neck, and the diaper area. It tends to worsen with heat and improve quickly once the baby cools down. Baby acne doesn’t respond to temperature changes in the same way and favors the face over skin folds.
What Makes It Better or Worse
Because baby acne stems from internal hormonal changes, there isn’t much you can do to prevent it. But certain products can make it worse. Lotions, ointments, and oils applied to the face tend to further clog already overactive pores, so it’s best to avoid them on affected areas. This includes baby oil, coconut oil, and heavy moisturizing creams.
Gentle daily cleansing with warm water is the simplest approach. You can use a mild, fragrance-free baby cleanser a few times a week, but scrubbing or picking at the bumps won’t speed things up and can irritate the skin. Rough fabrics, spit-up residue sitting on the cheeks, and drool can also aggravate the rash, so gently patting the face dry throughout the day helps.
How Long Baby Acne Lasts
Most cases of neonatal acne clear up on their own within a few weeks to a couple of months, without any treatment. The timeline depends on how quickly the baby’s hormone levels stabilize. By around three to four months, the vast majority of cases have resolved completely, leaving no scars or lasting marks.
There’s a less common form called infantile acne that appears between three and twelve months of age. Infantile acne can be more persistent and may include deeper bumps like nodules or cysts in addition to the typical whiteheads and pimples. It tends to last longer and occasionally requires treatment, so it’s worth mentioning to your pediatrician if acne develops or worsens after the three-month mark.