Common causes of itchy throat, cough and nausea include chronic pharyngitis, allergic laryngitis and viral colds. 1.. Chronic pharyngitis: there are various discomforts in the pharynx, such as foreign body sensation, itchiness, irritation, etc. Due to the stimulation of the back wall of the pharynx which is often stimulated by the more viscous secretions, frequent irritating coughs are often seen in the morning, and nausea is caused in severe cases. 2. Allergic pharyngolaryngitis: caused by contact with irritating gases, pollen, dust mites, etc., which can lead to itchy throat, cough, and nausea due to coughing irritation. 3. Viral colds: Viral colds are often accompanied by upper respiratory tract infections and symptoms such as itchy throat and cough. Because of the cough stimulation and viral release of toxins to stimulate the central nervous system, can produce nausea and other symptoms. If you have a scratchy throat, cough and nausea, you should go to the hospital in time to get a clear diagnosis and treatment.