The purpose of the study is to evaluate whether once daily topical 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 and calcipotriol 50 mcg/g in the gel vehicle in patients with scalp psoriasis.

The primary response criterion is the number of patients with absence of disease and very mild disease after 8 weeks of treatment.

Inclusion Criteria:

• Scalp psoriasis amenable to topical treatment with a maximum of 100 g of medication per week
• Clinical signs of psoriasis vulgaris on trunk and/or limbs, or earlier diagnosed with psoriasis vulgaris on trunk and/or limbs
• Extent of scalp psoriasis involving more than 10% of the total scalp area
• Investigator's assessment of clinical signs of the scalp of at least 2 in one of the clinical signs, erythema, thickness and scaliness, and at least 1 in each of the other two clinical signs
• Disease severity on the scalp graded as Mild, Moderate, Severe or Very severe according to the investigator's global assessment of disease severity

Exclusion Criteria:

• PUVA or Grenz ray therapy within 4 weeks prior to randomisation
• UVB therapy within 2 weeks prior to randomisation
• Systemic 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