Your age?  If in middle to late middle age it would no be a surprise to see a tapering of Cluster. But regardless of age, the variability of Cluster signs & symptoms is such that it's not possible to say why these shifts occur.

I just finished posting in the "CH's and your age?" thread, noting that my cycles improved, in severity and time between, the older I got (now 62, started in my 20's). However, since using Imitrex, the cycles seem to have gotten closer together and I wonder, what medications if any, have you used?

Thanks for the replies guys, couple familiar old faces and a couple new ones 

After reading your responses and doing some thinking I may have some ideas why the beast has been evolving on me. In sept. '10 I was injured pretty bad while training with the FD & ended up with a severely herniated L5/S1. The first discectomy didn't help so I had a second in aug 2011. I was in the midst of a cycle and told the anesthesiologist & neurosurgeon right before surgery that I was having CH's. They looked at each other, nodded & replied "we can take care of that for you". Turns out they gave me a mega dose of steroids IV post-op, that ended that cycle pretty much instantaneously.

The second theory I have is I ended up with severe sciatica due to FBSS/scar tissue/recurrent herniation/blah blah bad back stuff lol. I have been on 600 mg of gabapentin 3x a day for the last 3 years. Gabapentin/neurontin is listed as a CH treatment in quite a bit of medical texts, it does seem to help my sciatic nerves but slows down every other nervous system reaction too (you should see me trying to play video games that require quick reaction times).

Another observation, purely anecdotal is I started Batch's recommended D3 therapy, I haven't had a CH since the 2nd day on it, knock on wood, and my sciatica isn't bothering me as much as my lower back is now. Perhaps there is a strong connection between the D3 & nervous system? IDK, like I said, speculation, but thought I would share....