Hard to see but looks like mealy bugs to me. I find the best way for me is to wipe the affected areas with diluted alcohol. Or even a diluted soap and spray the plant. Rinse off about 15 minutes later.
I'm sure others will have some suggestions that are probably better than mine.
Kirk

So, I don't have to remove the affected leaves? How do you prepare your alcohol?

I just dilute it a little. Though I don't think it's really needed. The alcohol will help cut through that waxy protection mealy bugs have. I tend to remove the leaves if they're too damaged.

Kirk

I used 1:1 ratio. Even though I tried to be gentle, the more damaged leaves fell off. I checked the other three adeniums and thankfully, they're clear.

Giselapr, the alcohol helps.....I use cotton swabs, loosing up the tips and dip in alcohol.

Repeat second if first time doesn't work.

Marie

Thank you, Marie and Kadie. I'll keep your advice in mind if they come back!

You're welcome! And please keep us updated on the health of your plant.