I always (for at least the past year) seem to have excess phlegm in my sinuses. Every so often it comes out in my nose or mouth, and it's usually yellow. I definitely in recent weeks feel increasingly 'bunged up' in my face, like you do when (as a normal person) you're recovering from a cold. Is the colour of the phlegm a sign that I have an active infection? Or just ME immune dysfunction?
I don't think we have good evidence for there being such a thing as ME immune dysfunction. Yellow phlegm more or less means bacterial colonisation. If that is coming from the nose persistently it is likely to originate in the maxillary or frontal sinuses. Chronic low grade bacterial sinusitis is probably quite common although it was never my field and things have changed over the decades. Maybe an ENT opinion is in order.
I had persistent yellow gunk for a period early on. From about 3-18 months in if I remember. (I don't get it anymore.) I could always get some out if I did that gross thing where you suck from your sinuses into your mouth - but a lot would come with PEM and I would suck out quite a bit. I could never get it out by blowing my nose. I had a round of clavamox during that period but it had no noticeable effect. I also had a nasolayrongoscopy which observed only some small polyps and slight redness in the throat I think.
I do, from post-nasal drip. I've had it much of my life, certainly long before ME. It's exacerbated, though, by my own insistence on occasionally eating dairy, to which I'm now intolerant. (Lactase supplements mean I can digest it without discomfort, but it doesn't stop it making me phlegmy. )
Every morning without fail I have an amount approx the size of an almond of brown or yellow phlegm. I have to spend a few mins clearing it, it's been like that since about 5 yrs before becoming ill - so about 25 yrs. I then intermittently a few times through the day have the same but it's wetter, a smaller amount & either yellow or green. I just assumed it was 'normal' as I don't have an sense of a blocked nose or facial/sinus pain. I have often wondered if it might be a very low grade infection, but being already erroneously seen as a hypochondriac I wouldn't dream of seeing a Dr about it. Perhaps I should?
The only time I ever had yellow phlegm was two decades before ME when I got bronchitis that lasted about 7 weeks and took 2 lots of antibiotics to clear. I do get noticeable catarrh when I eat cow cheese although I’ve read this hasn’t been proven to be connected . I definitely don’t get it from goat or sheep cheese.