Steve Jobs isn't at 100%, but won't be leaving Apple (NASDAQ:AAPL).

In an open letter to the Mac faithful issued today, Jobs said that doctors have diagnosed a hormone imbalance that's robbing his body of protein and causing the noticeable weight loss that made headlines in 2008.

"The remedy for this nutritional problem is relatively simple and straightforward, and I've already begun treatment. But, just like I didn't lose this much weight and body mass in a week or a month, my doctors expect it will take me until late this Spring to regain it. I will continue as Apple's CEO during my recovery," Jobs wrote.

No doubt some will be skeptical. Not me. My eldest son has a combination of food allergies and celiac disease, which, as with Jobs, prevents his body from absorbing most proteins. There's no cure, but specialized foods ensure that he remains healthy.

But most people don't fully comprehend my son's predicament. Those who do have spent considerable time talking with us about what he can and can't eat. It makes me wonder whether Jobs' PR campaign has just begun.

CIO magazine contributor Rich Levin, a tech watcher who's also an old friend, says that's a good idea. "Good move on his part, PR wise. Now they should serve up some specifics so experts can comment and bring calm to investors," he wrote.

I agree. Apple needn't comment further, but having experts explain what Jobs faces and what the risks are would eliminate needless uncertainty. Jobs, for his part, says that he's done commenting. "So now I've said more than I wanted to say, and all that I am going to say, about this," he wrote.

I understand. Jobs' health is his business. Were he in danger of not being able to run Apple then, yes, we'd have a right to know. Barring that, the man has a right to privacy.

But those demanding full disclosure -- and there are many -- argue, rightly, that Jobs is more valuable to Apple than Mike Dell is to Dell (NASDAQ:DELL) or Mark Hurd is to Hewlett-Packard (NYSE:HPQ).

Plus, there's no obvious successor to Jobs. Bill Gates had Steve Ballmer for Microsoft (NASDAQ:MSFT). Google (NASDAQ:GOOG) has Larry, Sergey, and CEO Eric Schmidt. Who'll succeed Jobs? Marketing chief Phil Schiller? Not if the Mac faithful have a say.

Steve won't be leaving Apple soon. But he will someday. Until there's a succession plan in place -- one we all know and like -- this issue isn't going away.

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Fool contributor Tim Beyers wishes there was a cure for celiac. He had stock and options positions in Apple and Google at the time of publication.

Check out Tim's portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. The Motley Fool is also on Twitter as @TheMotleyFool. Its disclosure policy is 15 years young.