After three boys, I thought I’d seen all a baby butt could turn out—from poop paintings to corn kernels—but when my fourth child started getting weird acidic poop that literally seemed to eat her skin away, I was sort of baffled. Acidic diaper rash was not something I had heard a lot about, but it happens, and it is horrible.
What is acidic diaper rash?
Acidic diaper rash occurs when for one reason or another your baby’s poop becomes acidic in pH and burns the skin. For my baby, this was obvious by immediate bleeding rashes (when I knew she had just pooped). These bloody spots almost looked like she’d been poked repeatedly with a small pin and were only where the poop had touched.
Other types of diaper rash occur more frequently where the diaper touches the skin or in skin creases, but this rash will be very red, possibly bleeding, inflamed skin only where the poop is touching, and it will be there no matter how quickly you change the diaper. I think that’s the biggest tell that a rash is acid-poop based, it happens almost instantly.
Next, the poop that accompanies acidic diaper rash is often runny (diarrhea) and looks poorly digested, like there are often still recognizable chunks of lunch. In formula or breastfed babies that haven’t started solid foods, the poop just looks very runny and lacks the common seedy yellow appearance. It may also have an off odor that just doesn’t smell like normal poop, almost rancid or sour.
What causes acid diaper rash or acidic poop in babies?
Some babies can get acidic poop from high fruit intake, too much juice, or eating foods that are acidic, such as tomato sauce or citrus fruits, but in my baby girl’s case, it was fructose sensitivity (malabsorption). It can take some diet exploration to pinpoint the cause of acidic poop, but the cause is almost always dietary.
One of the easiest ways to identify a food allergy, intolerance, or sensitivity is to keep a diet log. Note days that the diaper rash, acid poop, or other symptoms of indigestion occur and find common factors, then cut one factor at a time from your baby’s diet to see what works. Breastfeeding moms will also need to track their own diet and avoid problem foods.
As fructose sensitivity is a common culprit of acid diaper rash, I caution that not all fruit will get a reaction. Bananas, for instance, are often fine and remember that high-fructose corn syrup can also create an issue ( “high fructose”).
Finally, while most dairy is alkaline, lactose intolerance can lead to acidic diaper rash as well. Unabsorbed lactose is fermented into lactic acid by bacteria in the colon, which will lower the stool (poop) pH.
How do you treat acid poop burns?
The most important step when it comes to rash treatment is to identify the dietary issue causing the rash and eliminate it. The butt burns actually heal quite quickly as long as the acid poops stop. In the meantime, it can help to avoid baby wipes by using either a small squirt bottle or just a quick butt rinse in the tub. As it’s the wiping motion that tends to hurt, just dab the skin dry afterward with a soft cloth, or if you’re brave, let that little bum air dry.
The best diaper rash cream I found for acidic diaper rash is the Triple Paste, though it’s best to avoid applying anything but fresh air until the burns are no longer actively weeping. Thankfully, so long as your baby’s diaper is changed quickly, the burns usually aren’t very severe, and it takes less than a day for the rash to look kind of scaly and red (like a thin scab over the burn). At that point, it’s fine to use a diaper rash cream or skin protectant. It will help things heal faster.