Signs and Symptoms of Childhood Asthma

Symptoms of an acute asthma attack usually develop over a period of hours or days. Symptoms tend to be worse at night, and attacks often occur between 2 and 4 am. Symptoms of asthma include:

• Coughing
• Wheezing
• Shortness of breath (dyspnea)
• Chest tightness or pain
• Rapid breathing
• Chest retractions due to labored breathing
• Irritation of the mouth and throat
• Thirst
• Need to urinate
• Tightness of the neck muscles
• Thick stringy mucus (especially at the end of the attack)
• Frequent bouts of weakness or tiredness

After an acute attack, inflammation of the airways persists for days to weeks although no symptoms may be present. This inflammation, however, increases the risk of further attacks, and therefore, must be treated with appropriate medications.

Differential Diagnosis of Childhood Asthma

Not all wheezing in childhood is due to asthma. When symptoms persist or start after the age of three, especially in combination with other allergic symptoms such as eczema, the diagnosis of asthma is much more likely.

There are several medical conditions that can cause wheezing, cough, and other symptoms of asthma in children that must be excluded:

• Upper respiratory tract infections (rhinitis, sinusitis, tonsil or adenoid enlargement)
• Lower respiratory tract infections (pneumonitis, bronchiolitis)
• Airway obstruction (i.e., laryngeal webs, foreign body aspiration, vocal cord dysfunction)
• Cystic fibrosis
• Bronchopulmonary dysplasia
• Gastroesophageal reflux disease (GERD)
• Congenital heart disease
• Pneumonia
• Tuberculosis
• Pertussis
• Swallowing dysfunction

Many children have their first episode of asthma in the first 3 years of life. During this period, it is difficult to distinguish a first episode of asthma from bronchiolitis, a viral infection of the bronchi and bronchioles, caused primarily by respiratory syncytial virus which is common in the fall and winter and affects most young infants.

Diagnostic Testing for Childhood Asthma

Establishing the diagnosis of asthma often occurs over a period of time and can be tricky particularly in infants and children younger than five. The clinical presentation of childhood asthma can vary significantly from children whose only symptom is coughing to children who are persistent wheezers and have difficulty breathing. Moreover, traditional pulmonary function tests such as spirometry, that are routinely used to diagnose asthma in adults and older children are very difficult to perform in infants and children younger than age five.

In general, the diagnosis of childhood asthma is based upon the child's medical history (e.g., signs and symptoms) and a physical examimination. Several diagnostic tests may also be performed to help the doctor establish the diagnosis of asthma and rule out other conditions that may cause similar symptoms.

• Chest X-ray helps to exclude other diagnoses (asthma does not cause changes in the x-ray)
• Sinus X-rays to exclude sinusitis
• X-rays of the gastrointestinal tract to rule out gastroesophageal reflux disease (GERD)

• Complete blood count (CBC)
• Serum eosinophil count - a "marker" of allergies
• Serum IgE antibody levels - elevated levels of serum IgE antibodies suggests an allergic state
• Arterial blood gas (ABG) analysis - once common, this test is now usually reserved for asthmatics who are very ill and are at risk of requiring mechanical ventilation (intubation)
• Skin testing for allergens
• Sputum testing

Pulmonary function testing (PFT) can be used to make a diagnosis, to assess the response to therapy, and to monitor the course of the disease. Also known as spirometry, this is a test that is performed to evaluate and measure lung function. Spirometry is a non-inavasive test that uses a device called a spirometer to measure the amount of air that is blown out of the lungs. During the test, the patient is asked to take a deep breath and then quickly blow it out into a mouthpiece that is attached to the spirometer until all of the air has been expelled from the lungs.