ENT :: Reason Of Throat Clearing For Almost 2 Months?

I'm posting on behalf of a close family member - somewhere around the beginning of December, she started experiencing frequent but very short dry coughs (literally "ahem ahem" and that's it). Over the weeks, the cough became less and less prevalent and the dry coughs were replaced with productive throat clearing - around late December the coughs were rarer and rarer while she frequently had to hem to clear the throat (every time there actually was something to clear so it was no longer dry).

Around the beginning of January both the hemming and coughing suddenly disappeared and for some three days, she did neither. Then the hemming came back and it stays up to today. It's not constant and varies highly around the day - sometimes she rarely ever hems and only starts in the evening, sometimes she does hem very frequently in the afternoon while in the morning and in the evening - nothing. There were also one or two days when suddenly the dry cough came back for some one hour and then disappeared. She also had a few days when the dysphonia was clearly hearable but now it seems to be gone. Now the only thing that's left is the hemming to clear her throat though most of the time it's either gone or rather weak now (though yes, there usually is a 1 or 2-hour period during the day when the throat clearing is more pronounced and some occasionals throat clearings on other occasions).

What may be the reason? There are no other symptoms at all and as I said, it varies highly depending not only on a day but also on the time of day. It's still pretty frequent but sometimes it's really frequent - and sometimes it only happens once in a while. As for her point of view, she says she hems cause she feels there is something to clear from the throat and she feels dryness there and as for the coughing (which happens very rarely now, as I mentioned) she says she does it when she feels dryness and there is this tingling sensation which makes her cough. In the last week she bought herself a A+E Vitamin + Aloe spray for dryness and it seems to greatly help her so that her hemming is greatly reduced - but it's still there. Also, she works with her voice (lecturer), if that's important.

Oh, and the description of our patient:

Age: 45

Sex: Female

Height: 5' 3"

Weight: 132lbs

Duration of complaint: around 7-8 weeks

Any existing relevant medical issues (if any): none

Current medications: none