The purpose of this study is to determine whether the combinational use of ammonium lactate lotion 12% (Lac-Hydrin) and halobetasol propionate ointment 0.05% (Ultravate) is safe and effective in the initial treatment and long-term maintenance of psoriasis. Patients will use both medications continuously for two weeks and those who obtain a good improvement based on investigator clinical assessments will be randomized to Lac-Hydrin lotion twice daily every day with placebo ointment or Ultravate ointment twice daily on weekends only for up to 24 more weeks.

This is a randomized, double-blind, placebo-controlled, clinical trial assessing the efficacy of Ultravate ointment in combination with Lac-Hydrin lotion in the treatment of plaque psoriasis. In the first phase, patients will be treated for two weeks with combination therapy using Ultravate ointment twice daily along with Lac-Hydrin lotion twice daily. After two weeks, psoriasis plaques will be evaluated to test treatment efficacy. Those patients with a significant clinical improvement per investigator clinical assessments, will be randomized in a 1:1 fashion into a maintenance phase and receive Lac-Hydrin lotion twice daily everyday with placebo ointment or Ultravate ointment twice daily on weekends only. Continuous use of Ultravate ointment will be discontinued following two weeks of treatment in compliance with its FDA indication. Patients will be evaluated every 4 weeks (monthly) through the maintenance phase. The purpose of this second phase of the study is to investigate whether use of Ultravate on weekends only can minimize risk of plaque recurrence, maximize duration of therapeutic effect, while limiting the need for the use of long-term continuous topical corticosteroid treatment. As well, the second phase of the study is to investigate whether twice daily Lac-Hydrin lotion has an impact in maximizing the duration of therapeutic effect as well as minimizing local cutaneous side effects such as skin atrophy and telangiectasia. Part of this clinical study consists of the use of patient and self-assessment questionnaires and the use of non-identifying digital photography of target lesions. The hypothesis is that Ultravate ointment on weekends only will be statistically more efficacious at maintaining an excellent initial clinical response and its combination with Lac-Hydrin lotion will help to minimize any local cutaneous side effects as well as enhance its therapeutic effect.

Inclusion Criteria:

• Subjects must be at least 18 years of age and in good general health as confirmed by a medical history.
• Females of childbearing potential must have a negative urine pregnancy test on Day 1 and must agree to use adequate birth control methods during the entire study.
• A clear diagnosis of plaque psoriasis must have been previously established and the disease must have been present at least 6 months.
• Subjects must have lesions suitable for evaluating response to test agents. The severity of the disease at Day 1 must be rated at least 2 (Mild) for each of the key psoriasis characteristics (scaling, erythema, and plaque elevation).
• Subjects must be able to understand the requirements of the study, abide by the restrictions, and return for the required examinations. All subject must sign the statement of informed consent approved for the study.

Exclusion Criteria:

• Subjects who are pregnant (determined from a urine pregnancy test on Day 1).
• Subjects who are nursing.
• Subjects with known hypersensitivity to any components of the test medication.
• Subjects requiring any other medication (topical or systemic) that may affect the course of the disease during the study period (e.g. antibiotics, sedating antihistamines).
• Subjects using biologics or any other systemic treatment for psoriasis within 12 weeks of entering the study.
• Subjects using systemic corticosteroids within 28 days of entering the study; subjects using topical corticosteroids or other topical therapies (other than emollients) at any location on the body within 1 week of entering the study.
• Subjects with overt pre-existing telangiectasia or skin atrophy at intended treatment sites.
• Subjects who are using any medication or has any disease which in the judgment of the investigator will interfere with the conduct or interpretation of the study.