They need light soil and good drainage.

I have not had this same plant long enough to offer skilled advice, Based on what I know from just growing plants for so long now, it looks to me like the sort of damage that results from being too dry.

I only posted a response to give the thread a bump to the top so you may receive some good assistance.

These plants don't make very good indoor houseplants, because they require heat to grow their best. Indoor temperatures, especially indoor air conditioned temperatures, just isn't enough to keep these plants happy. If they don't get the heat they require, then they'll shed their leaves and go dormant, much like they would in their native habitat.

Currently, I have two of these plants growing outdoors here in the hot and humid South, and both of them are growing like weeds. I may not be able to tolerate it, but these plants crave it. Not only that, but both of mine are currently blooming.

If you want this plant to thrive, then give it what it needs: indirect sunlight, fast draining soil, lots of water to keep the soil from drying out, and lots of that scorching summer heat. Without that heat, your plant will never be happy and would rather go dormant until the heat returns.

I went outside and snapped a couple photos of my Alocasia. I didn't bother taking photos of both plants, because they essentially look pretty much the same as one another. It's too hot to be staying outside any longer than I need to be. As I said, I can barely tolerate this heat, while my Alocasias thrive in it. Just as long as I keep them well watered, the hotter the weather gets, the bigger the leaves seem to get, as well as the more of them there are.