An allergy cough is most often a symptom of an allergic reaction. Allergies like hay fever can often cause congestion, sneezing, itchy skin, nose, and eyes, as well as allergic coughs.
More precisely, allergy coughs are caused by a response to a compound that the immune system identifies as harmful (as an allergen), and this triggers an allergic reaction. In some cases, conditions like asthma may also cause allergy coughs, especially when accompanied by other symptoms such as chest tightness, wheezing, and shortness of breath. An allergy cough doctor or a certified allergist can help diagnose the problem and find appropriate treatment methods to find relief from allergy coughs.