Beaucarnea recurvata (pony tail) has red splotches at leaf attachment point

After returning from vacation, it was clear to me that our two-metre tall pony tail palm was no longer in good shape -- although there is plenty of new growth (pale, though), it has lost many leaves and was looking very threadbare as compared to what I remembered (one notices these things better after an absence).

It was purchased in 2004 and has never been repotted. In the last couple months or so I've noticed a red blotchiness near the attachment point of the leaves. I suspect that this.. disease(?) is contributing to its accelerated loss of leaves.

Today we repotted it, using "cactus soil mix". I am hoping that that will help, as it was rather rootbound, but wanted to get some expert advice, if possible -- particularly as I see that someone here had already received knowledgeable assistance with these plants.

I've attached a photograph of the "red blotch" from a detached/fallen leaf.