Is prednisone useful as a diagnostic test?


Last Friday I finally had my appointment with a rheumatologist, after a six-month wait. She did an examination, asked a lot of questions, took a bunch of x-rays and blood tests. She wants to check for some other autoimmune diseases because I have a few symptoms, such as Raynaud's phenomenon and dry-eye syndrome, which are not usually typical of psoriatic arthritis.
Then she put me on a 10-day course of prednisone, as a test. She said if my symptoms are caused by inflammation, they will get better with the prednisone; if the drug has no effect, then there is a non-inflammatory cause (such as fibromyalgia).
The instructions for the drug were to take 3 pills for three days, 2 pills for three days, then taper to one pill. I took two doses on Friday but woke up Saturday with an upset stomach. Rather than stop the drug entirely, I decided to take only half a pill at time (I often have to do this, because I'm a very small person and the prescribed dosage of drugs is usually too much for me).
I've been able to tolerate half a pill if taken with food.
It's been three days now, and so far the results have been mixed. My shoulder felt better; I was able to sleep on my left side for the first time in four months. And the pain and itching of my psoriasis has completely disappeared!
But my back really hurt yesterday, and today I'm having neck problems. These could be from muscle spasms, which I guess would not respond to prednisone.
Yet I wonder if I would be getting a stronger response if I were able to tolerate a higher dosage of the drug. Or maybe it takes more time to fully work.
Has anybody else been given prednisone as a diagnostic test? Did you think it was useful? If I don't respond well to prednisone, does it mean I can't have psoriatic arthritis?

Hi hiker deb,

I’m not sure why your doc thinks Raynauds and dry eye are not typical with PsA.

I get very occasional transitory Raynauds, and symptoms of dry eye, and I know there are many others here who have diagnosed Raynauds and sjrogrens (mine is minor in comparison to fatigue and joints, so I’ve only mentioned it in passing to my Rhuemy who confirmed it was likely PsA associated).

With regard to the prednisone, it is a pretty good test for inflammation-associated disorders. It is such a strong anti-inflammatory that for most people, there will be a noticeable improvement within hours. It does depend on dose though, and you didn’t mention what strength the pills are (for pred they come in many different strengths). If for example, they are 5mg, and you are only doing half a pill three times a day, well 7.5 mg is a pretty low dose - I wouldn’t expect that to work miracles. For me, for example, it’s not enough to maintain inflammation reduction sufficient to allow me to feel remotely ‘normal’, and That’s on top of methotrexate and plaquenil, both of which are also having a big impact.

That said, everyone is different. You’ll also find a surprising number of people with both PsA and Fibromyalgia (with some theories the pain of the PsA can trigger the FM), which could be another explanation.

Sometimes it can take a little time to resolve, (i know its frustrating when youve been hoping for an answer), good luck.

Yes, my rheumatologist did the same thing with me, prescribed it as a diagnostic procedure. I was scared to death of the prednisone, but it worked like magic. Within 2 hours, I felt an improvement, and within a day or so, my swollen feet looked normal. The rheumy, consequently, was satisfied that my symptoms were the result of inflammation. A while later, I asked for another course of prednisone to take while we were travelling. It worked wonders again, and allowed me to do a lot more things than I could have otherwise, but after several days I started to get bad tempered, so I reduced the dose (and the benefits, of course). My doc really doesn't like prescribing it, and to tell you the truth, I really don't like taking it. But sometimes you gotta do what you gotta do. ;-)

I think the reduced dose, and the effect that had on you, will still give some useful information to the doctor. Interesting about the muscle pain. That could be because, taking the prednisone, you moved more easily and you inadvertently strained something. Don't forget to take notes so that you can report everything.

Glad you're making some progress!