Cough

[Froge]

At somewhat random moments throughout the day, I'll suddenly break into continuous coughing fits of over a minute long at a time because of acquiring an intense and unbearable itch in my throat. The feeling is rather bizarre: it's like someone is sticking a feather down my throat and tickling it, and no amount of coughing helps to stop the itch. However, in the instant of coughing, I can have momentary relief. So really, the only reason why I cough for a minute straight is because the itch is there for a minute, and then disappears. To prove my hypothesis that coughing does not stop the itch at all, I once went a minute straight without coughing when that itch appeared, and it indeed subsided once the minute was over. That minute was so unbearable I had tears flowing down my eyes.

The itch tends of appear when I'm on the verge of falling asleep in a moving vehicle, but not when I fall asleep in bed. Does this happen to anyone else?

[Acies]

Nope, sorry. I did once have a really nasty cough though (my throat would itch in the same way then). One day: Drank chocolate milk, biked intensively to get home - coughing fit - puked chocolate milk all over my bike.

Yeeah..

But to answer your question: No.

[Cranky Old Man]

At somewhat random moments throughout the day, I'll suddenly break into continuous coughing fits of over a minute long at a time because of acquiring an intense and unbearable itch in my throat. The feeling is rather bizarre: it's like someone is sticking a feather down my throat and tickling it, and no amount of coughing helps to stop the itch. However, in the instant of coughing, I can have momentary relief. So really, the only reason why I cough for a minute straight is because the itch is there for a minute, and then disappears. To prove my hypothesis that coughing does not stop the itch at all, I once went a minute straight without coughing when that itch appeared, and it indeed subsided once the minute was over. That minute was so unbearable I had tears flowing down my eyes.

The itch tends of appear when I'm on the verge of falling asleep in a moving vehicle, but not when I fall asleep in bed. Does this happen to anyone else?

Would that happen to be the SAME moving vehicle?
I could link you to an online symptom checker, but it's pretty obvious that the vehicle that you are refering to has also transported an animal like a dog, or a chemical (or seat cleaner) or asbestos, that you are having an allergic reaction to. It could be that your drowsiness is part of that reaction too - that your throat not only itches, but also swells, so that you don't get enough air.

[Froge]

Nope, I've gotten this itch from being in both my car as well as any bus. It just always happens when I'm near falling asleep.

[Cranky Old Man]

Nope, I've gotten this itch from being in both my car as well as any bus. It just always happens when I'm near falling asleep.

It's important to know whether you are falling asleep due to natural causes, like not having slept enough at night, or if your sudden drowsiness always occurs together with the rash, because in that case, you're falling asleep due to respiratory problems - the rash could be occuring deep in your lungs as well.

Anyway, "I see you have a cough"...
http://www.everydayhealth.com/symptom-ch...port/cough

Edit: Also, the transportation may vary, but when you start to feel the rash, look outside your car/bus window. Is the car/bus passing the same location? Is it next to an industrial area?

[Froge]

Nope. It has happened pretty much anywhere before.

I'm definitely falling asleep of natural causes, as the itch always occurs after I've fallen unconscious (I'm pretty sleep deprived); I would suddenly wake up feeling the itch.

[Cranky Old Man]

Nope. It has happened pretty much anywhere before.

I'm definitely falling asleep of natural causes, as the itch always occurs after I've fallen unconscious (I'm pretty sleep deprived); I would suddenly wake up feeling the itch.

Oh, after you've fallen asleep! In that case, you're probably snoring. Ask a passenger if you're snoring.

Edit: Also, if you're often sleep deprived, you might want to have your snoring fixed by either nose clips, or oxygen therapy, because it can get to the point where you get apnea (suffocation during sleep).