Asthma typically presents with a history of respiratory symptoms such as wheezing, shortness of breath, chest tightness and cough, and is characterized by underlying chronic airway inflammation[1]. In adults and older children, the diagnoses of asthma can be confirmed by spirometric evaluation, but in preschool children, asthma can be a diagnostic challenge. Recurrent wheezing occurs in a large population of children < 5 years, typically with viral upper respiratory infections, but deciding when this is the initial presentation of asthma is difficult. A careful history, exam, and trigger factors and response to bronchodilator medications, family history can be useful in establishing asthma diagnosis in this age group.

Asthma should be suspected in children with a history of wheezing if following symptoms are noted:

• Wheezing or coughing on physical exercise/activity, laughing or crying in absence of apparent respiratory
• A history of allergic disease (eczema or allergic rhinitis) or asthma in first-degree relatives
• Clinical improvement during 2-3 months of controller treatment and worsening after cessation

Symptoms may be triggered by many factors, including upper respiratory tract infections, activity, stress and environmental exposure to allergens, and tobacco smoke to name a few.[2][3]

In the 2017 update, the Global Initiative for Asthma (GINA) published guidelines for asthma management in children ages five years and younger. While medications are an important component of asthma management, it is important to remember that a multi-pronged approach to asthma management comprises several strategies, including education, skills training, clinical monitoring, and environmental control measures when necessary. The goals of asthma management include normal activity and good control of asthma symptoms as well as minimizing future risk from exacerbations and medication side effects. Also, another goal is to maintain lung function and lung development as close to normal as possible.[4]

The following section highlights a stepwise approach to asthma medications used for rescue and control in this age group. Step therapy is based on the domains of severity and control.[5]

Stepwise Approach to Asthma Medication for Asthma in Children younger than five years[6][7]

Children with intermittent asthma have respiratory symptoms <2 days/week, no night time respiratory symptoms, no limitation in day to day physical activity and 0-1 asthma exacerbations/year. These children should be treated with inhaled short-acting bronchodilator medication such as albuterol via inhalation. It should be available for rescue on an as needed basis. Oral administration of albuterol is not recommended because it has a slower onset of action and a higher rate of side effects as compared to the aerosol preparation. When given as an aerosol, albuterol provides relief of acute asthma symptoms in five to 15 minutes and lasts for approximately four to six hours. 

 Children with persistent asthma have respiratory symptoms ranging from > 2 days/week to daily or several times/day, night times awakenings >2/month, minor to significant limitation to normal daily activity = or >2 asthma exacerbations in 6 months, or wheezing = or > 4 times/year lasting for > 1 day and risk factors for persistent asthma as defined in the introduction. Steps two through four describe controller treatment recommendations for children with persistent asthma. A short-acting beta-2 agonist should also be available for rescue for asthma exacerbations. 

In step two, a low-dose inhaled corticosteroid (ICS) is the preferred initial treatment to achieve asthma control. It should be given for at least three months to establish effectiveness. Although pressured metered-dose inhaler with a dedicated spacer is the preferred device in children, a nebulizer with facemask/mouthpiece can also be used in children who cannot be taught effective use of spacer device. 

Step three is considered if asthma control is not achieved with three months of step two care. In these cases, doubling the initial low dose of ICS may be the best option. Alternatively, addition of daily leukotriene receptor antagonist (LTRA), such as montelukast to low dose ICS can be considered in children with history of allergic rhinitis or other atopic history. Before any step-up therapy, it is important to consider an alternative diagnosis, check correct inhaler technique, confirm good medication adherence and enquire about risk factors such exposure to allergens or cigarette smoke.

Step four is recommended when a child fails to achieve good control on step three level of care, despite a good medication adherence and correct inhaler technique. Step four care includes both the continuation of controller therapy and referral of the child to an asthma specialist for further evaluation and treatment recommendations. There is insufficient data on inhaled corticosteroids and long-acting beta-2 agonists combinations to recommend their use in this age group.

Children with asthma should be assessed at regular intervals, typically every 2-6 weeks while gaining control and every 1-6 months to monitor control. Adjustments to therapy (step up or step down) can be made as necessary. At each visit, medications should be reviewed for adherence, efficacy, and potential adverse effects. Also, children with seasonal asthma exacerbations may require further evaluation and treatment for allergies. Annual influenza immunization is an important consideration for all asthmatic children. The use of pulmonary function/spirometry is recommended for children > 5 years of age to establish the diagnosis, and at least every 1-2 years to monitor lung function.

Asthma Action Plans[6][8][9]

Asthma action plan is a written document in which family/caregiver is provided with up-to-date instructions regarding daily asthma medications, recognition of symptoms that show asthma control deterioration, response when these symptoms are identified, and steps to take in the case of an asthma emergency. This is developed by medical providers in partnership with family/carers.   

Asthma Medication Classes: Reliever Medications [10][11][7]

Inhaled short-acting beta-2 agonists (SABA) (e.g., albuterol, levalbuterol) are the preferred and most commonly used options for quick relief of asthma symptoms and bronchoconstriction. Potential adverse effects include tremors, tachycardia, and palpitations. These adverse effects are seen more often during initial exposure.

Asthma Medication Classes: Controller Medications[10][11][7]

Inhaled Corticosteroids (ICS) are the preferred option for the initial management of mild persistent asthma and are a component of treatment plans for moderate and severe persistent asthma. Local side-effects may include dysphonia and oropharyngeal candidiasis. Use of a spacer device and having child rinse his or her mouth with water after using an ICS decreases the risk of oral thrush. High-dose corticosteroids are associated with systemic side effects, such as reduced growth velocity.

Combination therapy with an ICS plus long-acting beta-2 agonist (LABA) bronchodilator has been used in older children and adults with asthma. The combination of fluticasone propionate and salmeterol as a dry powder inhaler (diskus) has been evaluated for safety down to age four years. Efficacy data was extrapolated from patients ages 12 years and older. There is very limited data in children less than age four years. The aerosol preparation of Salmeterol and Fluticasone is FDA approved for ages 12 years and older. There is a boxed warning advising that long-acting beta-2 agonists such as salmeterol increase the risk of asthma-related death.

The leukotriene modifier, montelukast, is the only leukotriene modifier indicated for use in this age group and is available in either granules or chewable tablets depending on the age. It is an alternative option either alone or in combination with inhaled corticosteroids depending on the level of asthma severity and control. Safety and efficacy are not established for asthma in children younger than 12 months.

Systemic corticosteroids (tablet, suspension or intramuscular (IM) or intravenous (IV) injection) given for short term treatment, also known as burst therapy (usually given for three to five days) are important early in the treatment of severe acute exacerbations. In young children, the suspension is often better tolerated and accepted than tablets. 

A pMDI with a valved holding chamber is the preferred delivery system. For children 0 to 5 years of age, a face mask is recommended over a mouthpiece for children < 4 years of age. Different sized masks are available. A valved holding chamber allows for the medication to go to the lungs instead of impacting the back of the throat. It also helps with coordination of actuation.

A nebulizer device with either a face mask or a mouthpiece is an alternative method; however, not every medication is available as a nebulizer solution. 

Asthma is a serious health and economic concern in the United States, costing $56 billion each year. The average cost to care for a child with asthma was $1039 in 2009. Asthma surveillance data from the CDC shows that one in 11 children have asthma, which equals seven million children. Uncontrolled asthma disrupts daily life and causes one in two children to miss at least one day of school. This averaged to about 10.5 million missed school days. In 2009, there were 479,300 asthma-related hospitalizations, 1.9 million asthma-related emergency department visits, and 8.9 million asthma-related doctor visits.[12][13][14]