Hi, this is Bakubaku. Did you know petroleum jelly comes in different grades? I didn't until I looked into it — and it turns out the difference really matters for eczema skin.
4 grades by refinement
From least to most refined: (1) Yellow petrolatum — the cheap drugstore kind; more impurities, which can irritate sensitive skin. (2) White petrolatum — further refined; commonly used in hospitals. (3) Propeto — refined further; pure enough to be used in ophthalmology. (4) Sun White — Propeto refined even more; the highest purity available in stores.
So the order is: yellow → white → Propeto → Sun White. The further right, the fewer impurities and the gentler on skin (and yes, the higher the price).
Even Propeto didn't work for me
In my case, everything up to and including Propeto didn't suit my skin. The greasy over-sealing kept my facial redness from ever fading. When inflamed skin can't breathe, bacteria can apparently multiply between the jelly and the skin. But when I switched to Sun White, the redness stopped getting worse. These subtle differences really do matter for eczema skin. Of course, this is just my case.
Sun White P-1 (high-purity petroleum jelly)
The highest-purity petrolatum sold in Japan. I use it as the sealing step after Avène. (PR: contains affiliate links)
Check the base of your prescription ointment too
One more important thing: prescription ointments are often steroids mixed into a base like petrolatum or Propeto. Ever changed hospitals and felt like the same-strength steroid worked differently? That might be the base. It's worth finding out what your ointment is made of — and talk to your doctor about anything that seems off.
If your petrolatum moisturizer feels 'meh', switching grades is worth a try. My full routine is in the "Avène + Sun White" article.