A dry cough might be transmissible or communicable, depending on the reason. Post-nasal drip, or mucus trickling from the back of the nose into the throat, can cause dry coughs. A dry cough can also be caused by smoking (smoker's cough). A dry cough can also be caused by allergies. However, none of these conditions are communicable. It is possible to spread a dry cough as part of a cold or illness. Take measures like washing your hands more frequently and protecting your mouth.