Effect of Sex Hormone During the Menstrual Cycle on Capsaicin Evoked Cough Responses

The study aim is to investigate if changes in sex hormones during the menstrual cycle affects cough sensitivity in females and males with mild allergic asthma. Female subjects will be grouped according to natural cycle, or taking oral contraceptives. Male subjects will act as the control group.

The study will have a total of 3 visits separated by at least 24 hours. Screening Period (Visits 1) - For All Subjects. Eligible subjects will be identified during the initial screening procedures with measures of spirometry, hyperresponsiveness to methacholine, complete history, physical examination, allergen skin test, and capsaicin cough challenge. For female subjects, this visit will occur during Day 1-5 (follicular phase) of the menstrual cycle. Subjects meeting the eligibility criteria will be randomized to Sequence A or Sequence B. Sequence A will require Visit 2 to occur during menstrual cycle days 1-5 (follicular phase) and Visit 3 to occur during menstrual cycle days 21 - 25 (luteal phase). Sequence B will require Visit 2 to occur during menstrual cycle days 21-25 (luteal phase) and Visit 3 to occur during menstrual cycle days 1 - 5 (follicular phase). During Visit 2 and 3 subjects will undergo measures of spirometry, hyperresponsiveness to methacholine, capsaicin cough challenge, allergen skin test, sputum and blood collection. Visit Windows Each visit must be separated by a minimum of 24 hours. Study visits can be performed in the morning or afternoon, however for each subject the timing should be consistent with Visit 1 at the same time of day ± 2 hours.