After three boys, I thought I’d seen all a butt could turn out—from poop paintings to corn kernels—but when my fourth baby started getting weird acidic poop that literally seemed to eat her skin away, I was sort of baffled. Acid diaper rash was not something I had heard a lot about, but it happens, and it is horrible.
So, what exactly is acid diaper rash, and how do you spot it?
Acid diaper rash occurs when for one reason or another your baby’s poop becomes acidic in pH and literally 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 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-based, it happens almost instantly.
Next, the poop that accompanies acid diaper rash is often runny and looks poorly digested, like there are often still recognizable chunks of lunch. In babies that haven’t started solid foods, it just looks very runny and lacks the common seedy appearance. It may also have an off odor that just doesn’t smell like just poop, almost rancid.
What causes acid diaper rash or acidic poop?
Some babies can get acidic poop from high fruit intake or foods that are high in acid themselves, such as tomato, 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 it is almost always a dietary cause.
One of the easiest ways to track a food allergy or sensitivity is to keep a diet log. Note days the rash or acid poop occur and find common factors, then cut one factor at a time to see what works. 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 fine) and remember that high fructose corn syrup will also create an issue (“high fructose”).
How do you treat acid poop burns?
In this case, the most important thing is to identify the dietary issue causing the rash and eliminate it. The 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 dry afterwards.
The best diaper rash cream I found for this was the Triple Paste, though I would avoid applying anything but fresh air until the burns are no longer actively weeping. They, at least if your baby is changed quickly, are usually not very severe, and it takes less than a day for the rash to look kind of scaly and red (this is like a thin scab over the burn) at that point it’s ok to use the cream and it will help things heal faster.