Infection would be the leading possibility. I would expect a chest x-ray to rule out a pneumonia as well as possible blood tests to further elucidate the cause.
Assuming infection has been ruled out, other possibilities can include post-nasal drip from rhinitis, GERD, or asthma. If these options are considered, appropriate testing (i.e. allergy testing, pulmonary function tests, upper GI series/24-hr pH study) can all be considered.
These options can discussed with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
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