J.M.
My son has extreme allergies (food and seasonal). We tried Singular with him over a year ago and noticed a major personality shift with him. He went from being an easy-going kid to a very fussy kid. We took him off the Singular and he went back to being himself.
We have given him Liquid Claritin but with little success. We have recently started Liquid Zyrtec. It works okay for him. Mostly we just keep him indoors when the allergy reports are high and if he is really miserable (lots of coughing or sneezing) then we give him Liquid Benadryl.