My 2 years old cough since september less or more but always cough. what doctor should i see?7&

Cough: If your child has been coughing since September, allergies may be the culprit. Start with the pediatrician.

Many possible causes: There are anatatomic abnormalities, allergies, infections, developmental issues. You have to sit down with a good generalist who is not wearing "blinders" and he/she will get a thorough history and exam and appropriate lab and X Ray reports and studies and figure out what's going on with your baby.

Start with your: child's pediatrician. If you have already seen their regular doctor for this and discussed it, the other specialists to consider are an allergist, a pediatric pulmonologist (lung specialist), an ENT(ear, nose and throat) and a gastroenterologist (gastroesophageal reflux can cause a long standing cough)....but again, start with your child's regular pediatrician, who can guide you.