The purpose of this study is to evaluate whether once daily treatment for up to 8 weeks of calcipotriol 50 mcg/g plus betamethasone 0.5 mg/g (as dipropionate) gel is safe and more effective than betamethasone 0.5 mg/g (as dipropionate) in the gel vehicle, calcipotriol 50 mcg/g in the gel vehicle or the gel vehicle used alone in patients with scalp psoriasis.

The primary outcome is the proportion of patients with absence of disease or very mild disease after 8 weeks of treatment.

Main Inclusion Criteria:

• Scalp psoriasis amenable to topical treatment
• Psoriasis vulgaris on trunk and/or limbs
• Extent of scalp psoriasis involving more than 10% of the total scalp area
• Disease severity on the scalp graded as mild or worse by the investigator
• Consenting out-patients of 18 years or above

Main Exclusion Criteria:

• PUVA or Grenz ray therapy within 4 weeks prior to randomisation
• UVB therapy within 2 weeks prior to randomisation
• Systematic treatment with biological therapies, with a possible effect on scalp psoriasis within 6 months prior to randomisation
• Systemic treatment with all other therapies than biologicals, with a possible effect on scalp psoriasis (e.g., corticosteroids, vitamin D analogues, retinoids, immunosuppressants) within 4 weeks prior to randomisation
• Any topical treatment of the scalp (except for medicated shampoos and emollients) within 2 weeks prior to randomisation
• Topical treatment of the face, trunk and/or limbs with very potent WHO group IV corticosteroids within 2 weeks prior to randomisation
• Current diagnosis of erythrodermic, exfoliative or pustular psoriasis