Diaper Rash in Newborns: What Causes It, How to Prevent It, and What Actually Clears It Up

The first time you see it — that patch of angry pink skin on your one-week-old's bottom — it feels like you did something wrong. You didn't. Almost every baby gets diaper rash at some point, and almost every case is the same simple thing: soft newborn skin spent a little too long against a wet or soiled diaper.

The good news is that the fix is not complicated and it does not require anything you cannot buy at a drugstore. What matters is doing the small things consistently — and knowing the handful of signs that mean it is not a plain rash anymore. Here is what the AAP, Nemours KidsHealth, and MedlinePlus actually say, with nothing invented in between.

01What actually causes diaper rash

"Diaper rash" is a category, not one thing. The AAP groups the causes into four buckets, and knowing which one you're looking at changes what you do about it.

Irritant rash — by far the most common. This is the pink-to-red patch you get when urine and stool sit against the skin for too long. Seattle Children's is direct about the culprit: "Stool left on the skin can be very irritating because it contains bacteria." It shows up on the parts a diaper actually touches — the buttocks, the front, the thighs — and usually spares the deep skin folds of the groin. It gets worse during a bout of diarrhea or a stretch of teething.

Yeast (candida) rash. When the diaper area stays warm and damp for long stretches, the yeast that lives on everyone's skin can overgrow. Per the AAP, a yeast rash looks like "shiny, bright red or pink patches with sharp edges" and tends to settle into the groin folds — the exact spots an irritant rash usually spares. It is common after a course of antibiotics, because antibiotics kill off some of the friendly bacteria that normally keep yeast in check. Yeast will not clear with plain barrier cream — it needs an antifungal.

Bacterial rash (impetigo). Less common, but the one you don't want to miss. The AAP describes it as bright red skin around the anus, or "yellow crusting, weeping, or pimples." Seattle Children's similarly notes that "Bacteria cause sores, yellow scabs, pimples or draining pus." This one needs a call to the pediatrician.

Allergic reaction. Some babies react to a dye, fragrance, elastic, or preservative in a particular brand of diaper or wipe. The rash tends to match wherever the offending material touches — a ring around the waistband, patches under the elastic. Switching brands usually settles it down.

02How to prevent it in the first place

Prevention is boring and it works. MedlinePlus puts the whole strategy into one sentence: "The best treatment for a diaper rash is to keep the skin clean and dry." Everything below is a way of doing that.

03How to treat a rash that has already started

For a plain, red-but-not-broken irritant rash, the treatment is the prevention routine, done more strictly, plus a much thicker layer of barrier cream. Nemours KidsHealth says most rashes improve within two to three days of doing this well.

04Wipes, water, and what to actually clean with

Regular baby wipes are fine on healthy skin for most babies. When there's already a rash, they aren't the friend they usually are — the alcohol or fragrance in some brands stings, and even the mild ones can drag against inflamed skin. Nemours KidsHealth recommends "a wet washcloth instead of baby wipes" for babies with sensitive skin or an active rash.

The lowest-friction option — literally — is a small squirt bottle of warm water. Squirt, dab dry with a soft cloth, air a beat, cream. It sounds fussy for one change, but it is the fastest way to turn a raw bottom around. For the whole basic diapering routine when nothing is wrong, see our guide to changing a newborn diaper.

05How to tell if it's yeast (and why barrier cream won't cut it)

If a rash isn't improving after two or three days of the routine above — or if it's a shiny bright red with sharply defined borders and it's crowded into the skin folds — think yeast. Small "satellite" spots around the main patch, per MedlinePlus, are another giveaway. It is especially common after antibiotics, because antibiotics knock down the bacteria that normally keep yeast in check.

Yeast rash needs an antifungal cream, not just barrier paste. MedlinePlus lists the usual options: "Nystatin, miconazole, clotrimazole, ketoconazole." Some are over-the-counter and some are prescription — a quick call to the pediatrician will tell you what to use and how long. Keep doing the changing, cleaning, and air-drying routine while you treat it; damp skin is what let the yeast get going in the first place.

06When to call the pediatrician

Most rashes never get to this list. But if any of these show up, don't try to wait it out at home.

07The routine that keeps it from coming back

Once the skin has healed, most parents can drop back to fragrance-free wipes and skip the cream at every change. Some babies — especially the ones who get rashes with every bout of loose stool or teething — do better with a thin protective layer of zinc-oxide cream on healthy skin all the time. It doesn't hurt, and it saves you from starting from zero the next time your baby has three dirty diapers in a row.

Diapers are the task new parents do more than anything else, and small improvements in the routine compound fast. If you're still learning the mechanics, our changing a newborn diaper guide covers the basics, and what's normal for newborn poop will tell you which colors and textures are worth a second glance. The rest of the newborn learning curve — burping, sleep, when to call the doctor — lives on our newborn basics page, each piece sourced the same way this one is. And if you are still pregnant, our free week-by-week planner puts the prep that makes those first weeks easier right where it belongs: in the weeks before the baby arrives.

Questions parents actually ask

Newborn Weeks is planning help, not medical advice — always follow your own doctor, midwife, or pediatrician.