Evaluation of Adrenal Suppression Potential and Pharmacokinetics of Halobetasol Lotion 0.05%

Inclusion Criteria: 1. Subject is male or non-pregnant female and is 12 to 16 years 11 months of age. 2. Subject has provided written informed assent and was accompanied by the parent or legal guardian at the time of assent/consent signing. The parent or legal guardian has provided informed consent for the subject. 3. Subject has a clinical diagnosis of stable plaque psoriasis involving a minimum of 10% body surface area (BSA) within the Treatment Area. The "Treatment Area" is defined as the entire body exclusive of the face, scalp, groin, axillae, and other intertriginous areas. 4\. Subject has an Investigator's Global Assessment (IGA) score of at least three (3 = moderate) at the Baseline Visit. 5\. Subject is willing and able to apply the test article as directed, comply with study instructions and commit to all follow-up visits for the duration of the study. 6\. Females must have a negative urine pregnancy test (UPT) at the Screening and Baseline Visits and agree to use an effective form of birth control for the duration of the study. Exclusion Criteria: 1. Subject has spontaneously improving or rapidly deteriorating plaque psoriasis. 2. Subject has guttate, pustular, erythrodermic or other non-plaque forms of psoriasis. 3. Subject has a physical condition which, in the investigator's opinion, might impair evaluation of plaque psoriasis, adrenal axis function (e.g., Addison's Disease, Cushing's Syndrome) or which exposes the subject to an unacceptable risk by study participation. 4. Subject has used any phototherapy (including laser), photochemotherapy or systemic psoriasis therapy including methotrexate, retinoids, cyclosporine or biologics within 30 days prior to the initiation of treatment with the test article. 5. Subject has used systemic corticosteroids (including oral or intramuscular) or topical, inhaled or intranasal corticosteroids within 30 or 14 days, respectively, prior to Part B of the Screening Visit and/or the subject has used systemic or topical corticosteroids between Part B of the Screening Visit and the initiation of treatment. 6. Subject has had prolonged exposure to natural or artificial sources of ultraviolet radiation within 30 days prior to the initiation of treatment or is intending to have such exposure during the study that is thought by the investigator to likely modify the subject's disease. 7. Subject has used topical psoriatic therapy including tar, anthralin, retinoids, vitamin D analogs (e.g., Dovonex®) within 14 days prior to the initiation of treatment with the test article. 8. Subject has used emollients/moisturizers on areas to be treated within one day prior to the initiation of treatment with the test article. 9. Subject is currently using lithium or Plaquenil (hydroxychloroquine). 10. Subject is currently using a beta-blocking medication (e.g., propranolol) or angiotensin converting enzyme (ACE) inhibitors (e.g., lisinopril) at a dose that has not been stabilized, in the opinion of the investigator. 11. Subject has a history of sensitivity to any of the ingredients in the test article. 12. Subject is pregnant, lactating, or is planning to become pregnant during the study. 13. Subject is currently enrolled in an investigational drug or device study. 14. Subject has used an investigational drug or investigational device treatment within 30 days prior to Visit 1 (Screening). 15. Subject has been previously enrolled in this study and treated with the test article. 16. Subject has an irregular sleep schedule or works night shifts (cortisol levels exhibit physiological diurnal variation). 17. Subject has a screening Cosyntropin Stimulation Test (CST) with a post 30-minute stimulation cortisol level of less than equal to 18 μg/dL. 18. Subject is known to be noncompliant or is unlikely to comply with the requirements of the study protocol (e.g., due to alcoholism, drug dependency, mental incapacity) in the opinion