Hi Phil, It seems your question is too difficult for this panel.
For what it is worth during my questioning of many hundreds of
asthmatics this was one question I always asked, "do you have any
itchy scalp problem, or external forearm or shin area frontal skin
area problem patches."
It would appear this kind of problem "piggybacks" asthmatic effect and
commonly is a stress sensitive problem.
It is very strange.
Wether that may be your particular problem only time will tell, if
there is no response from these resident medical gurus.
Steroidal creams usually help if that were the case, but stress
control is the key to minimising the effect if it is neuro-sensitive.
If it is the problem I am thinking of, you will have a tendency to
scratch and remove the small heads off the items which commonly result
in swelled and sore  glands in the back of your neck.
If this is your particular problem it is a lifetime pleasure.
Hopefully someone might post some further information proving me wrong
which will allow your question to be properly answered.
I will leave the rest of your question for the gurus.
By the way, how often have you previously been using antibiotics?
For what it is worth, try drawing a graph of when your asthma symptoms
began and where you might have used antibiotics, it might be
interesting for you.
Cheers, Merlin.