When I hear persistent dry cough and nasal congestion worse at night the first thing I think of is reflux. It causes an irritant cough when microaspiration of refluxed material occurs and nasal swelling due to the exposure of the posterior nasal airway to an acid environment. An antacid will help the swelling but the cough will not respond to n antacid and the reflux will have to be treated. If your baby is bottle fed, you can thicken her formula with a tsp of rice cereal per ounce to decrease the liquidity and discourage reflux. You should also have her upright after meals for at least an hour and possible have her sleep with the head of her bed elevated about 45 degrees. If these measures do not relieve the cough, she will need further testing to determine the severity of the reflux. All babies have some reflux as infants but it should not be leading to cough and nasal stuffiness. Some babies also cry a lot both from the nasal congestion and the heartburn. If this is the case, she would cry and arch her back, seem relieved after feeding a bit but then start to be uncomfortable again a few minutes after. This is another clue to reflux. Significant reflux must be evaluated with visualization of the esophagus, stomach and small intestine to assure there is no other structural abnormality contributing to it such as malrotation. Milk protein intolerance can also be a contributing factor and the upper GI small bowel follow through study would provide a clue to this if there appeared to flocculation of the material in the small intestine. This would be treated with a hypoallergenic formula.