Painful sore throat, but no leaking - what might it be?

[Deneb]

In the morning after using my CPAP (I've been using it for about a month, and I keep it on all night pretty consistently), I wake up with a painfully sore throat. It fades after a few hours, but recurs every morning.

The first suspect is mouth-breathing, of course, but my APAP has never reported an excess leak rate higher than 0.04 L/s, and it's almost always 0.00 L/s. When looking at the detail graphs in Resscan, I see occasional transient small leaks (probably my waking up in the middle of the night and resettling the mask), but the line is mostly just flat. This leads me to believe that I'm not mouth breathing or leaking. When I called my DME, they had no suggestion other than mouth-breathing. Any ideas?

I do tend to have a bit of dry mouth, due to various medications. But I've never had a morning sore throat like this before.

[Snoredog]

sore throat when first starting out with therapy is common. Make sure you use a humidifier.
Put a water bottle on your night stand to keep things moistened up. Use of the mouthwash BIOTENE
will help keep things moistened. It is found right next listerine and other mouthwashes.

You experience this because the greater airflow from CPAP, your salivary glands have not yet compensated for
the extra airflow, it can take some time for them to catch up.

[OldLincoln]

Another possibility is nasal drip. I had the sore throat for a long time and went to the doc thinking strep throat. He gave me a sample of some nose spray and it was gone in 2 days.

[crossfit]

I had it really bad the first few days on apap. I turned my humidifier way up and it fixed it. About a week later I turned it back down a notch and still no sore throat. Sometimes now I can go down to 1 or 2 on the humidifier but if I do it only in passover mode that sore throat comes back with a vengeance.