A Histamine Pharmacodynamic Biomarker to Guide Treatment in Pediatric Asthma (HAS3)

Eligibility Criteria

• 1. A diagnosis of asthma based on physician diagnosis
• 2. A diagnosis of uncontrolled asthma based on Asthma Control Test (ACT) score within the last 3 months or at screening
• 3. Evidence of allergic sensitization based on allergy skin test or allergy blood test results
• 4. Individuals who are currently being treated with asthma guideline-based therapy
• 5. Males and females 6 through 17 years of age at time of enrollment
• 6. Willing to provide written permission/assent to participate
• 7. Children who self-identify as African American/black (identify both 1st degree (parents) and 2nd degree relatives (grandparents) as African American) or Caucasian/white (self-report of 1st and 2nd degree relatives as Caucasian)
• 1. For females, positive pregnancy test (by urinary hCG) or lactation at the time of the study
• 2. Any other chronic disease states such as history of premature lung disease, bronchiectasis, cystic fibrosis, or any chronic lung disease other than asthma.
• 3. Chronic abnormal conditions of the liver or kidney, immunologic/hematologic, or neoplastic disease as determined by the PI (the following questions will be asked at initial screening to identify children with potential abnormal kidney function:
• 4. Inability or unwillingness to have blood drawn as described in the protocol schedule of events and consent, or inability or unwillingness to cooperate with study procedures.
• 5. Clinically significant abnormal safety laboratory values as determined by study physician
• 6. Previous history of adverse drug reaction to Levocetirizine (LTZ)
• 7. Unwillingness or inability to washout of medications that affect histamine response
• 8. Active eczema at the site where histamine laser doppler probe will be place(forearm) on the day of histamine laser doppler iontophoresis
• 9. Age 18 years or older at the time of enrollment.
• 10. Those whom are pregnant, prisoners, and/or wards of the state.
• 11. Currently on or has been on Tricyclic Antidepresants in past 30 days