Patients suspected of having asthma typically present with a history of episodic shortness of breath associated with chest tightness and variable wheezing and coughing. Typically there are a number of triggers, such as extremes of air temperature and humidity; air pollution; strong odors, such as from perfume and cleaning agents; dust; and smoke.

If individuals are known to be atopic, then exposure to common environmental allergens, such as trees, weeds, grasses, animal dander, mold, dust mites, and cockroaches, can be potent triggers for their symptoms, depending on their particular atopic profile.

Because between 10% and 20% of adult asthma may be work related, adult-onset asthmatics should always be asked regarding occupational exposures and hobbies that may expose them to potential allergens. For younger nonsmoking patients with a typical history, many clinicians make a diagnosis of asthma and start therapy without consulting other specialists.

Many patients with this symptom complex are diagnosed with asthma by their primary care physicians without any physiological baseline assessment, such as pre-and post-bronchodilator response. This is suboptimal. A baseline physiological assessment is essential for gathering data to establish severity as well as to assess when a patient has reached his or her personal best.

Furthermore, a physiological assessment could reveal a non-obstructive pattern suggesting interstitial lung disease. Also, a physiological assessment could show that a patient’s degree of dyspnea is disproportionate to his or her spirometry, in which case other diagnoses should be considered and further testing performed.

When patients first present and, perhaps more importantly, when patients don’t respond optimally to asthma therapy, the provider must consider the conditions that may mimic or exacerbate asthma.

In the adult population, the most common conditions that need to be ruled out in asthmatics are allergic or nonallergic rhinitis with postnasal drainage, gastroesophageal reflux disease, and, in smokers who have smoked more than 10 packs per year, chronic obstructive pulmonary disease.

Patients with allergic rhinitis may have significant postnasal drainage that leads to cough wheezing and shortness of breath that can mimic asthma. Patients with gastroesophageal reflux disease can have bronchoconstriction just as a result of acid refluxed into the esophagus stimulating bronchoconstriction through a neural reflex, or they may induce bronchoconstriction as a result of refluxate being aspirated into the lungs.

Paradoxical vocal fold motion disorder (PVFMD), also known as vocal cord dysfunction (VCD), may mimic or complicate asthma. The paradoxical closure of the vocal folds classically during inspiration, but also seen during expiration, is associated with cough wheezing and shortness of breath and often coexists with postnasal drip and gastroesophageal reflux disease.

Some patients who have PVFMD and laryngopharyngeal reflux (reflux into the throat) without frank gastroesophageal reflux disease may have PVFMD in isolation. Some such patients may microaspirate this refluxate, leading to asthma symptoms or reports of recurrent pneumonia.

In the past, we thought of chronic obstructive pulmonary disease patients as generally having a minimal bronchodilator response and no evidence of airway hyper-responsiveness.

Now we recognize that many patients with a clinical history and histological features closely compatible with chronic obstructive pulmonary disease have higher significant bronchodilator response, evidence of airway hyperresponsiveness, or both.

Truncated flow-volume loops and laryngoscopic findings of paradoxical closure confirm the diagnosis. Many lung conditions can have asthmatic features, including sarcoidosis, hypersensitivity pneumonitis, and, to a much lesser extent, other interstitial lung diseases.

Bronchiectasis, a dilation of airways due to chronic inflammation causing destruction of the airway wall, can present with symptoms and objective physiological assessments similar to those of asthma.

Allergic bronchopulmonary mycosis, chronic colonization of the airways leading to an allergic response, is often a complication of asthma, but may also develop in patients who have bronchiectasis for other reasons, such as cystic fibrosis, primary ciliary dyskinesia, and immunodeficiency states, such as common variable immunodeficiency, which render patients more susceptible to recurrent infections.

Patients who have postinfectious bronchiolitis or bronchiolitis for any number of other reasons, underlying collagen vascular disease and certain prescription and illicit drugs may have a clinical presentation suggestive of asthma.