Swimmers Cough due to chlorine irritant. How to stop?

Patient: Long story short my 12 year son swims year round. Living in NJ he has been swimming indoors except for the summer and is being affected by the chlorine. He has developed a “chlorine cough” that interrupts his practice. We have taken him to a Pulmonologist and after three visits came to the conclusion it is not asthma. We have tried prescription strong cough suppressants and they don’t work. They now want to start him on an inhaler with steroid that may not work since he does not have asthma. Do you know how this can corrected? – Karen

Symptoms: Coughing while swimming only