When you have asthma, any upper respiratory infection -- like a cold or the flu -- can affect your lungs causing inflammation and airway narrowing. It is important to take measures to stay healthy and be aware of any asthma symptoms, even mild, so that you avoid a more serious asthma attack.
American Academy of Allergy Asthma & Immunology: "What is an Allergy/Asthma Specialist?" American Academy of Family Physicians: "Asthma: Questions to Ask When It Doesn’t Get Better?" Merck Source: "Questions to Ask Your Doctor."