Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM) 

Environmental Triggers of Asthma
Differential Diagnosis of Asthma

Learning Objective

Upon completion of this section, you will be able to

• identify five conditions that may be confused with asthma in children, and
• identify five conditions that may be confused with asthma in adults.

Differential Diagnosis in Adults

The first step in dealing with the asthma patient is to make sure it is asthma. Although, many cases of recurrent cough and wheezing in children and adults are due to asthma, other conditions are often misdiagnosed as asthma. In adults, the differential diagnosis of asthma includes

• chronic obstructive pulmonary disease (COPD),
• chronic bronchitis or emphysema,
• congestive heart failure,
• gastroesophageal reflux disease,
• mechanical obstruction of the airways,
• tumor/neoplasm, and
• vocal cord dysfunction.

Infrequent causes of wheezing include

• pulmonary embolism,
• pulmonary infiltrates with eosinophilia, and
• some medications (e.g., angiotensin-converting enzyme (ACE) inhibitors) (NHLBI 1997).

Differential Diagnosis in Children

In children, chronic cough is a problem, which needs differentiation asthma, or not asthma? Chronic productive cough with purulent sputum is a reason for concern in children and is not usually a symptom of asthma. The younger the child, the more the need to exclude underlying disease at an early stage (de Jongste and Shields 2003).

Wheezing in children can be an allergic (i.e. asthma) or nonallergic response (Lemanske 2003; Weinberger 2003). Nonallergic wheezing in children occurs during acute infections, including viral bronchiolitis. Coughing and wheezing in bronchiolitis is difficult to distinguish from asthma. The differential diagnosis of children with frequent respiratory infection and wheezing should include

• airway obstruction with a foreign body,
• bronchitis,
• pneumonia/bronchiolitis,
• cystic fibrosis,
• bronchopulmonary dysplasia (in premature infants),
• dysmotile cilia syndrome,
• alpha-1-antitrypsin deficiency, and
• immunodeficiencies (NHLBI 1997; NHLBI 2003).

(See Table 1 below.)

Upper airway diseases

• Allergic rhinitis and sinusitis

Obstructions involving large airways

• Foreign body in trachea or bronchus
• Vocal cord dysfunction
• Vascular rings or laryngeal webs
• Laryngotracheomalacia, tracheal stenosis, or bronchostenosis
• Enlarged lymph nodes or tumor

Obstructions involving small airways

• Viral bronchiolitis or obliterative bronchiolitis
• Cystic fibrosis
• Bronchopulmonary dysplasia
• Heart disease

Other causes

• Recurrent cough not due to asthma
• Aspiration from swallowing mechanism
• Dysfunction or gastroesophageal reflux

• Chronic obstructive pulmonary disease (COPD)
• Chronic bronchitis or emphysema
• Congestive heart failure
• Pulmonary embolism
• Laryngeal dysfunction
• Mechanical obstruction of the airways (benign and malignant tumors)
• Pulmonary infiltration with eosinophilia
• Cough secondary to drugs (ACE inhibitors)
• Vocal cord dysfunction

Key Points

• Many medical conditions may be confused with asthma at initial diagnosis.

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