Sickle cell disease is a common genetic disorder and there is ample evidence that asthma is a common co-morbidity with an asthma prevalence of 2% to 45% compared with 12.8% in African American children without sickle cell disease. Acute chest syndrome (ACS) contributes to the cause of death in up to 60% of deaths in sickle cell patients and there is a strong relationship between having asthma and the risk of developing ACS and an increased risk of death.