The child only cough without other symptoms, the first consideration may be cough variant asthma, inhalation of irritating gases, mycoplasma infection. If the child cough for dry cough, no fever, cough sputum, no asthma and other symptoms, and cough for a long time, the effect of drug treatment is poor, to consider the cough variant asthma, if through the nebulized inhalation of asthma medication, the cough is significantly reduced or even completely relieved, more support for this diagnosis, but also by going to the hospital to check the chest X-ray, lung function, bronchial diastolic test, etc. to further confirm the diagnosis. The child suddenly inhaled irritating gases, can also cause cough, especially may have damage to the laryngopharyngeal mucosa of the gas, early just appear cough. Mycoplasma infection is characterized by an irritating dry cough in the early stages, and there may be no other symptoms in the early stages; checking for mycoplasma antibodies may assist in the diagnosis. When there is only a cough, take your child to the doctor in time to find out the cause and then treat it.