Psoriasis

INTRODUCTION

A chronic, immune-mediated skin disorder of unknown aetiology which affects 2–4% of the population. It appears most often between the ages of 10 and 30 yrs, although its onset can occur any time from infancy to old age.

Principles of management

• Provide education, reassurance and support

• Promote general measures such as rest, and holidays preferably in the sun

• Advise prevention, incl. avoidance of skin damage and stress if possible

• Tailor treatment (incl. referral) according to the degree of severity and extent of the disease

TREATMENT OPTIONS

Topical therapy

• Tar preparations

• Topical corticosteroids

• Calcipotriol

Treatments can be monotherapy or combined. Rotational therapy often required.

Chronic stable plaque psoriasis

For trunk and limb psoriasis, apply:

• LPC 6% + salicylic acid 3% cream or ointment, bd for 1 month

• If insufficient or flare, add moderately potent to potent topical corticosteroid ointment, d until clear (2 to 6 wks) or

• If inadequate response, calcipotriol + betamethasone dipropionate 50 + 500 mcg/g ointment, d until clear (about 6 wks)

Once controlled, reduce potency of steroid and withdraw if possible. Continue tar as maintenance therapy.

Palmoplantar psoriasis

Treat as for trunk or limb psoriasis; however, higher dose of salicylic acid is required if hyperkeratotic, i.e. LPC 6% + salicylic acid 6%. Also consider earlier use of calcipotriol, given common resistance to topical therapy.

Scalp psoriasis

• Potent corticosteroid lotion or shampoo d until skin is clear (2 to 6 wks), then coal-tar shampoo for maintenance

• If thickened scale, add LPC 6% + salicylic acid 3% in aqueous cream bd

• If inadequate response, calcipotriol + betamethasone dipropionate 50 + 500 mcg/g gel, d until clear (within 2 wks)

Facial psoriasis

• Methylprednisolone aceponate 0.1% ointment or fatty ointment, d for 2 to 6 wks or 1% hydrocortisone for children

• Once controlled, LPC 2% + salicylic acid 2% in aqueous cream at night

Flexural (inverse) and genital psoriasis

Methylprednisolone aceponate 0.1% ointment or fatty ointment, d for several wks (up to 2 wks in children). Once controlled, LPC 2% in emulsifying ointment at night.

Expert therapy

• Narrowband ultraviolent B phytotherapy (UV-B): 2–3 times/wk for few months

• Methotrexate: can have dramatic results in severe cases

• Cyclosporin (not recommended long term)

• Acitretin (vitamin A derivative): never use in females of child-bearing age

• Biological agents—for example, anti-TNFα agents (e.g. infliximab)

Guttate or small plaque psoriasis

• Plaques are likely to respond to milder topical treatments

• 4% LPC and 4% salicyclic acid in cream base, bd

• Otherwise treat as for chronic stable plaque psoriasis on trunk