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There is no cure for psoriasis, although there are effective treatments. Treatment is suppressive, aimed at inducing a remission or making the extent of psoriasis tolerable to the patient. For the majority of patients, the disease follows a chronic course, interspersed with periods of remission. Relapses are difficult to predict and cannot be prevented with topical therapy.
Those patients with extensive disease, who need systemic treatment, will normally be under the supervision of a consultant dermatologist, because of the potential toxicity of these drugs. The dermatologist will also be involved in the care of difficult cases where the site or unresponsive of rashes, are important factors.
The need for treatment will often be dictated by the patient's own perception of his or her condition. A simple regimen for the initial topical treatment of chronic plaque psoriasis can be outlined as follows:
Emollients - use as frequently as needed. See section 13.2.1 Emollients
Use of Soap substitutes and bath additives
For localised plaque psoriasis, for example on the elbows or knees, the following topical preparations (listed in no particular order) can be tried. The exact choice will depend on the feelings of the doctor and patient about the different treatments, e.g. side-effects.
Topical steroids - can be very useful for limited psoriasis, flexural psoriasis or extremely unstable erythrodermic psoriasis. The weaker steroids often do not work very well on thick patches, but may work better on the face or in the skin folds. (see section Corticosteroids (topical))
Tar preparations - can help, but many find them "messy" and can stain clothing. See section 13.5.2 Preparations for psoriasis
Dithranol - can cause severe skin irritation and should only be prescribed by those experienced in its use. It should only be used for short contact periods of 30-60 minutes. Dithranol in Lassar's paste, however, is used for long contact - 12-24 hours. This can cause a problem of contact for partners and is "messy". (see section 13.5.2 Preparations for psoriasis)
Calcipotriol / calcitriol - more expensive than other topical treatments, but equally or slightly more effective than the alternatives (other than for guttate psoriasis when vitamin D derivatives are generally less effective). (see section 13.5.2 Preparations for psoriasis)
Combination of calcipotriol and steroids - Combining the use of corticosteroid with calcipotriol may be beneficial in chronic plaque psoriasis. The drugs may be used separately at different times of the day or used together in a single formulation. Eczema co-existing with psoriasis may be treated with a corticosteroid, or coal tar, or both.
For more widespread plaque psoriasis, for example, on the trunk or the limbs, the same treatments may be appropriate, with the proviso that dithranol may be impractical to apply to several small lesions.
Olive oil - can be used on infected and heavily scaled scalps to remove thickened skin.
Tar based shampoos - usually first line, followed by a 2% salicylic acid preparation, a coconut oil/tar combination ointment, a potent topical steroid preparation, or calcipotriol scalp application.
Hydrocortisone cream 1%
Clobetasone butyrate 0.05% cream (Eumovate®)
Trimovate® cream (clobetasone / oxytetracycline / nystatin)
Common in the elderly and represents psoriasis mixed with discoid eczema or eczema craquele. Treat with moisturisers and topical corticosteroid ointments.
Do not use: Calcipotriol (Dovonex®) or Dithrocream or Tazarotene (Zorac®) if the psoriasis is eczematous as it will be irritant.