Here’s the secret women over 50 in Japan use to soothe their eczema for good. And most women in America have never even heard of it.

They call it akagire, the deep cracks that split across the knuckles and down the sides of the fingers and burn when anything touches them. The women there named it centuries ago, and they worked out how to soothe it.

My grandmother still lives on a small farm outside Osaka, and she is 82, and her hands have never once cracked. Every night of her life she has rubbed the same beef tallow balm into her hands and her face. When I was little I used to sit and watch her do it and think, why is Grandma rubbing fat on her face? I thought it was just an old country habit, and when I moved to America I forgot all about it.

She took my hand at her kitchen table and turned it over. She said that after menopause the skin stops making the fat that holds the surface together, so it dries out and splits. (The doctors here call that a fissure, and every woman with eczema knows that sharp burn when anything touches one.)

Then she said the part that made me put my tea down. “You put it on at bedtime, you’re awake at 2 in the morning putting it on again, and the crack gets deeper every night.” That was my life, every single night, and I had never told her any of it.

My grandmother said a crack like that is an open nerve. A regular cream is made to sit on top of the skin, so on an open crack it sits right on the nerve, and that’s why it burns. Even plain Vaseline stung me by the end, which I didn’t think was possible.

On the plane home I read the backs of all my tubes. The first thing on almost every one of them was water, and the Cortizone has alcohol in it, and anybody who has put rubbing alcohol on a cut knows what that does to open skin. A fat has no water and no alcohol in it, which is why my grandmother’s balm never burned her.

She told me two more things the Japanese way does differently. Wash in warm water, never hot (hot water feels good on itchy skin for a minute and then it’s worse), and put the balm on right after the bath while the skin is still a little damp, all over, not just on the bad spots.

I want to be fair to the steroid tube, because it does work. It stopped my itch by the next morning every time, which is exactly why I kept going back to it.

But it also thins the skin. Mine went shiny and thin like tissue paper, so the crack came back sooner and deeper, and every time I stopped it came back worse, and the answer at the doctor was always a stronger tube. A hand that keeps cracking is a prescription that keeps getting refilled.

I don’t blame my doctor. She was doing what she was taught, and a balm from a farm outside Osaka was never going to come up in a 10-minute appointment. But the day I understood all this, I stopped feeling stupid and I got angry about the 15 years I’d lost.

Beef tallow has been used on Japanese farms for generations for dry, cracked skin (walk into a drugstore there and you’ll find shelves of animal-fat creams). It’s the closest fat there is to the fat our own skin makes, so the skin takes it in instead of leaving it sitting on the crack.

I couldn’t bring my grandmother’s balm home (they make it on the farm and nobody sells it), so I ordered the cheapest tallow I could find online. It smelled like cooking beef. It had gone hard and grainy, so I had to dig it out with my fingernail, and it sat on my hands in a greasy film that ended up on my pillowcase. One woman in the reviews said it was like slathering her face with bacon grease, and another said it brought ants into her bed.

I nearly quit right there. I called my grandmother and told her maybe tallow only worked in Japan, and she told me what to look for instead. The fat first on the label, no water at all, and honey, because hers has honey in it. I added my own list after that first jar: whipped so it never goes hard, smelling of anything but beef, and a real-size jar.

I was so nervous that first night, because putting anything on is the hardest part. You never know if it’s going to sting. I took about half a pea on my fingertip and tried a tiny patch on one knuckle first, just in case.

It didn’t sting. It felt like putting an ice pack on it! The pale blue disappeared into my skin while I watched, and in about a minute my knuckle just looked like skin again with nothing sitting on top. So I did the rest of both hands, turned off the lamp, and slept through the whole night for the first time in longer than I can remember.

In the morning I checked my pillowcase, which is white, and there wasn’t a mark on it.

That was two years ago, and my hands haven’t cracked since. I’ll be honest about what didn’t change, though. My knuckles are still a little darker than the rest of my hand, and every January I still get one dry patch on my right thumb, but now it just gets dry and the balm takes care of it.