Asthma is a chronic lung disease characterized by inflammation of the airways and bronchoconstriction, making breathing difficult. Common symptoms include coughing, wheezing, shortness of breath, and chest tightness or pain. Inhalers provide medication directly to the lungs and help control asthma symptoms, maintain lung function and normal activity levels, and prevent attacks. There are two main types of inhalers - metered dose inhalers that use short bursts of aerosolized medicine and dry powder inhalers that use powdered medication.