13.5.2 Preparations for psoriasis

General guidance

• The initial treatment for stable plaque psoriasis should be topical. However, in those with greater than 20% body involvement systemic therapy may be necessary at the outset.
• For mild conditions reassurance and an emollient may be all that is necessary.
• Salicylic acid is useful in hyperkeratotic and sealing conditions to enhance the rate of loss of surface seals.
• Coal tar is more active than salicylic acid and has anti-inflammatory, anti pruritic and keratolitic properties. Coal tar paste should not be used on the face.
• Dithranol is the most potent topical preparation available for psoriasis and should be applied only to the lesions. Proprietary preparations such as Dithrocream cause less staining and irritation then dithranol paste and are therefore more appropriate.
• Calcipotriol is a vitamin D analogue for the topical treatment of plaque psoriasis, a scalp solution is also available. It appears to be more effective than traditional treatments and does not have an unpleasant odour or stain clothing, it therefore has significant advantages for patients. Care must be taken not to exceed the recommended maximum dosages.
• Acitretin is a systemic retinoid for the treatment of severe resistant or complicated psoriasis, it is also useful in some congenital disorders of keratinisation. It should only be prescribed by a specialist. Adverse effects (sometimes quite severe) need careful monitoring and the drug is a powerful teratogen requiring adequate contraceptive measures for at least one month before treatment initiation (and negative pregnancy test), throughout therapy and for at least two years after a course of the drug.
• It may be reasonable to prescribe a short course of a weak topical corticosteroid for face, flexural and genital psoriasis.

​Recommended drugs

Topical therapy

Salicylic Acid ointment 2%

Dithrocream

Calcipotriol (cream/ointment/scalp lotion)

Dovobet ointment (1 month only if not reviewed by specialist)

Dovobet gel (1 month only if not reviewed by specialist)

Systemic therapy

Acitretin (specialist use only)

Drug Traffic Light Key:

Green – On Formulary

Amber – Restricted use, see local guidelines      

Purple – Specialist use/initiation

Red – Non Formulary

Relative Costs Key (where indicated):

£££££ - high

£££ - moderate

£ - low