Individualized Therapy For Asthma in Toddlers

Inclusion Criteria: * 12-59 months of age. * If the child is not currently taking long-term asthma controller therapy (meaning that the child has taken no inhaled corticosteroid or leukotriene receptor antagonist medication whatsoever over the past 6 months), then one of the following criteria must be met: * Daytime asthma symptoms more than two days per week (average over the past 4 weeks), * At least one nighttime awakening from asthma (over the past 4 weeks), * Two or more asthma exacerbations requiring systemic corticosteroids in the previous 6 months, * Four or more wheezing episodes in the previous 12 months. * If the child is currently taking long-term asthma controller therapy (meaning that the child has taken daily or intermittent/as-needed inhaled corticosteroid or leukotriene receptor antagonist over the past 6 months), then one of the following criteria must be met: * Taking inhaled corticosteroid or leukotriene receptor antagonist for more than 3 months (or more than 90 days) out of the previous 6 months (or 180 days), * Daytime asthma symptoms more than two days per week (average over the past 4 weeks), * More than one nighttime awakening from asthma (over the past 4 weeks), * Two or more asthma exacerbations requiring systemic corticosteroids in the previous 12 months, * Four or more wheezing episodes in the previous 12 months. * Up to date with immunizations, including varicella (unless the subject has already had clinical varicella). * Willingness to provide informed consent by the child's parent or guardian. Exclusion Criteria: * Allergic reaction to the study medications or any component of the study drugs, including (but not limited to) urticaria, rash, angioedema, or hypotension following delivery, * Chronic medical disorders that could interfere with drug metabolism/excretion (for instance chronic hepatic, biliary, or renal disease), * Chronic medical disorders that may increase the risk of drug-related injury, including (but not limited to): * Osteogenesis imperfecta (increased risk of bone demineralization/fracture with corticosteroid therapy), * Crohn's disease, ulcerative colitis, juvenile rheumatoid arthritis, clotting disorders, or Factor deficiency (increased risk of bleeding with corticosteroid therapy), * G6PD deficiency (increased risk of hemolytic anemia with acetaminophen use), * Phenylketonuria (potential for aspartame exposure with study interventions), * Seizure disorder treated with anticonvulsants (risk of acetaminophen toxicity with carbamazepine), or * History of clotting disorders or Factor deficiency (increased risk of bleeding with corticosteroids), * Co-morbid disorders associated with wheezing including (but not limited to) immune deficiency disorders, cystic fibrosis, aspiration, clinically-relevant gastroesophageal reflux, tracheomalacia, congenital airway anomalies (clefts, fistulas, slings, rings), bronchiectasis, bronchopulmonary dysplasia, and/or history of premature birth before 35 weeks gestation, * Significant developmental delay/failure to thrive, defined as 5th percentile for height and/or weight or crossing of two major percentile lines during the last year for age and sex, * History of a near-fatal asthma exacerbation requiring intubation or assisted ventilation, * No primary medical caregiver (e.g., a nurse practitioner, physician assistant, physician, or group medical practice such as a hospital-based clinic) whom the subject can contact for primary medical care, * Three or more hospitalizations in the previous 12 months for wheezing or respiratory illnesses, * Treatment with 5 or more courses of systemic corticosteroids (oral, intramuscular or intravenous) in the past 6 months, * Current use of higher than step 2 NAEPP asthma guideline therapy * If receiving allergy shots, change in the dose within the past 3 months.