What can I do for my toddlers allergies?

Need suggestions. My 20 month old has allergies. She loves being outside. Today she was outside playing in the grass with her sister and now she’s itching her eyes and coughing and has a runny nose and can’t sleep. Besides the obvious of keeping her inside what can we do to make her less miserable. All of the allergy medicine I’ve looked at says 2 years and up. She’s very small for her age. She’s only 19 lbs (maybe 20 on a good day).