Although it is generally thought that if frequent cough & cold is there then it is mostly due to lung or respiratory issues. But it is not always due to this reason.
Many congenital heart diseases can presents with this issue. There are multiple types of holes in the heart that leads to increase blood flow into the lungs and can cause cough & cold by causing increase fluid secretion in lungs alveoli.
Causes can be: large ventricular septal defect (VSD), large patent ductusarteriosus (PDA), atrio-ventricular septal defect (AVSD/AVCD) with large VSD or it can be cardiac diseases that lead to decrease oxygen concentration in the body; e.g.transposition of great vessels (d-TGA) with large VSD, truncusarteriosus, total anomalous pulmonary venous connection (TAPVC/TAPVD) etc.
In the above mentioned heart diseases, besides normal blood flow to both lungs, there is an additional blood supply through the large holes in the heart.
In these types of diseases,patient disease should be addressed aggressively and early treatment should be given to the child.
Please see section of common cardiac condition of www.childrenheartcare.com for detailed description of above mentioned cardiac diseases.