Your question just prompted me to do some googling. I never really understood what was causing that and during that time I had a shit load of weird lesions on my skin....I contacted someone at Tufts and long story short we came to a conclusion that it was a result of histamine. The following may be of interest to you because histamine can also cause brochoconstriction and perhaps you're having some kind of an issue with a medication elevating your histamine....
Histamine exerts its actions by combining with specific cellular histamine receptors. The four histamine receptors that have been discovered in humans are designated H1 through H4, and are all G protein-coupled receptors (GPCR). Histamine receptors in insects, like Drosophila melanogaster, are histamine-gated chloride channels that function in inhibition of neurons.[6] Histamine-gated chloride channels are implicated in neurotransmission of peripheral sensory information in insects, especially in photoreception/vision. Two receptors subtypes have been identified in Drosophila, HClA and HClB.[7] There are no known GPCRs for histamine in insects.
Type Location Function
H1 histamine receptor Found on smooth muscle, endothelium, and central nervous system tissue Causes, bronchoconstriction, bronchial smooth muscle contraction, vasodilation, separation of endothelial cells (responsible for hives), and pain and itching due to insect stings; the primary receptors involved in allergic rhinitis symptoms and motion sickness; sleep regulation.
2. Bronchoconstriction (definition) is defined as the narrowing of the airways in the lungs (bronchi and bronchioles). Air flow in air passages can get restricted due to 3 factors: - a spasmodic state of the smooth muscles in bronchi and bronchioles - an inflammation of the airways - excessive production of mucus due to an allergic reaction or irritation caused by mechanical friction of air (due to shear stress), overcooling or drying of airways. Bronchoconstriction is common in people with respiratory problems, such as asthma, COPD, and cystic fibrosis.
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I'm one of the least knowledgable persons on this forum, but I do believe that in some weird awkward way this could be part of your problem.
Be well