What kind of allergy medicine is best for children under 3 with severe allergy problems?

Several choices. For anaphylaxis, self injectable Epinephrine is recommended. Antihistamines available include: Allegra suspension down to 2 years old, Clarinex syrup down to 6 months old, Claritin syrup down to 2 years old, xyzal (levocetirizine) syrup down to 6 months old, zyrtec syrup down to 2 years old; palgic syrup down to 1 year old. Also, singulair is approved down to 6 months old. For severe allergies, see allergist!