Schwarzbein mentions how high carb intake causes insulin levels to rise and this causes excess eicosanoid hormone production.

Eicosanoids relax or contract smooth muscle groups (ie: bronchial muscles). Eicosanoids also are involved in the immune system.

She specifically mentions how asthma can be traced to high carb intake (due to excess production of eicosanoids)...

Maybe our allergies are kinda the same(?) We are seeing an improvement because the eicosanoid hormones are getting back into proper levels.