Coughing in a 2-year-old child can be a result of post-nasal drip, where mucus from the nose drips into the throat. This could be a symptom of allergies. You could try giving your child an antihistamine like Aerius or Claritin. Your pharmacist can show you the product and advise you on the correct dosage based on your child's weight and health condition. It is also a good idea to use Hydrasense to irrigate and clean the sinuses to prevent mucus from building up and dripping down the throat. Avoid using it within 30 minutes before bedtime. Feel free to ask if you have any other questions!