ASIT naïve patients sensitized to grass pollens will be recruited for the study. All of them
will be instructed to treat bothersome in-season symptoms when they appear (on as needed, pro
re nata basis) with rescue medication. They will be given 5 different options and will be
informed about the effects of each of them in order to make their optimal choice for
different symptoms and their combination: local decongestant (xylomethazoline, when
congestion is leading), local antihistamine (azelastine, when itching, sneezing and rhinorhea
a predominant), nasal corticosteroid (momethasone, when all nasal symptoms are pressing and
no adequate relief is obtained form the other 2 local treatments), oral antihistamine
(bilastine, when itching and sneezing persist despite the local treatments) and oral
corticosteroid (prednisolone, when any or all symptoms become unbearable despite the other
suggested treatments). Patients who are reluctant to use immunotherapy or who are too late to
initiate it will be randomized to be treated with the listed medications on as needed basis,
the nasally applied formulations will be followed by either HPMC to prolong and enhance their
effect (Group HPMC) or placebo (lactose powder) (Group Placebo) to serve as control. Patients
indicated and willing to carry out ASIT will be treated according to the standard protocol
with grass allergens sublingually (Staloral #688) and will receive rescue medication (Group
Immunotherapy).