It's sometimes hard to tell
Can my child go to school?
Allergies can make your child feel drowsy and some medications to treat the allergies can as well. If your child is finding it difficult to concentrate or the symptoms are too bothersome, it may be better to keep her home so she can rest and sleep. If her symptom, such as sneezing, runny nose, and tiredness, are better with antihistamines, she should be okay to go to school.
Can I prevent my child from getting allergies?
There is no approved medication for preventing allergies. However, allergy immunotherapy can treat allergies unlike medications that just alleviate the symptoms. See your friendly allergist for recommendations!