Diagnosis of asthma The diagnosis of asthma is usually made based on the patient’s symptoms and medical history (Table 1). Table 1 Is this asthma? Asthma should be considered whenever any of the following signs and symptoms are present: ■ Wheezing – a high-pitched wheezing sound on exhalation, especially in children (a normal chest physical examination does not exclude asthma) ■ History of any of the following: ■ Cough, especially worse at night Recurrent wheezing Recurrent dyspnea Recurrent chest tightness ■ Symptoms occurring or worsening at Symptoms appear or worsen at night, waking the patient ■ Seasonal onset or worsening of symptoms ■ Family history of eczema, cushings, or asthma and other allergic diseases ■ Symptoms appear or worsen after exposure to fur-bearing animals Inhalation of human chemicals Temperature changes House dust mites Medications (aspirin, receptor blockers) Exercise Pollen Respiratory (viral) infections Smoking Violent mood swings ■ Symptoms respond to asthma treatment Patients with colds that are “chest deep” or take more than 10 days to heal Pulmonary function tests can help establish the diagnosis of asthma by assessing the severity of asthma and the reversibility and variability of airflow limitation. Respiratory flow testing is recommended to determine airflow limitation and its reversibility to clarify the diagnosis of asthma. An increase in FEV. of ≥12% (or ≥200 mL) after administration of bronchodilators is suggestive of reversible airflow limitation, which is consistent with asthma (however, most asthmatics do not demonstrate reversibility on every test, so repeat testing is recommended). Maximal expiratory flow (PEF) measurement can provide very important assistance in the diagnosis and monitoring of asthma. PEF is best measured using the patient’s own peak flow rate meter and compared to his/her own previous best value. An increase in PEF of 60 L/min (or ≥20% increase over pre-inhalation bronchodilator) after inhalation of a bronchodilator, or an intra-day variability of more than 20% (>10% for 2 readings per day), suggests a diagnosis of asthma. Other diagnostic tests: In patients with symptoms consistent with asthma but normal lung function, measurement of airway responsiveness to acetylcholine, histamine, mannitol, or exercise excitation can help establish the diagnosis of asthma. Allergen skin test, or determination of serum specificity I : The likelihood of an asthma diagnosis is increased if allergens are detected, and this test also helps to identify risk factors causing asthma symptoms in the individual patient. Diagnostic difficulties ■ Cough variant asthma: Some patients with asthma have a chronic cough (frequent at night) as their main or even only symptom. In these patients, the presence or absence of pulmonary function variability and airway hyperresponsiveness is of particular importance. ▪ Exercise bronchoconstriction: For most patients with asthma, physical activity is an important trigger of asthma symptoms and may be the only cause for some patients (including many children). An exercise test (8-minute run) can establish a definitive asthma diagnosis. ▪ Children under 5 years of age: In infants and young children, not all wheezing is asthma. For children in this age group, the diagnosis of asthma is mostly based on clinical judgment and should be reviewed regularly as the child develops. (Asthma in the elderly: The diagnosis and management of asthma in the elderly is complicated by a variety of factors, such as poor perception of symptoms, perception of dyspnea as a “normal” manifestation of old age, and reduced expectations of health status and activity. The differential diagnosis of asthma and COPD is particularly difficult and may require experimental treatment. ▪ Occupational asthma: Workplace-acquired asthma is often underdiagnosed. Diagnosis requires a clear history of exposure to occupational irritants; no asthma symptoms prior to the occupation; and a clear relationship between symptoms and the workplace (symptoms improve away from the workplace and worsen upon return to the workplace).