Let me throw out another potential cause that worked for my parents: baby with a small butthole. They used lube and their fingers and gradually stretched it.
That baby may or may not have been me. The doctor our baby has had never heard of such a thing, so maybe it’s just hooey.
>The cause of colic is generally unknown. Fewer than 5% of infants who cry excessively turn out to have an underlying organic disease
Could be small asshole, but the thing about colic is usually there's simply NOTHING that can be fixed.
People want to think you can fix something, or that there is some underlying disease. With colic that is rarely the case. That's the maddening thing about it, there's nothing wrong per se with the child, nothing to fix, no cause to be found. People offer solutions constantly, you keep trying to solve it, but at the end of the day the child simply acts like they hate life and everyone in it and there's simply nothing you can do but wait it out for months. You can drive yourself mad trying to find something wrong when there simply is no curable solution but time.
That baby may or may not have been me. The doctor our baby has had never heard of such a thing, so maybe it’s just hooey.