Dr Alison Roberts outlines the different types of psoriasis and reviews the topical, systemic, and biological interventions that can be used to manage this condition

Psoriasis is a common skin problem, which follows a chronic course interspersed with periods of remission.1 The condition is not infectious and does not scar the skin.2 It affects about 2% of the population and occurs equally in men and women, at any age. There is a hereditary component: a child who has one parent with psoriasis has approximately a 1 in 4 chance of also developing the condition.2 There is no cure for psoriasis but symptoms can be controlled.2 Many patients can be managed in primary care, but a significant number will benefit from treatments that are provided or initiated in secondary care.

Assessment

In managing skin disease it is important to take a detailed history (see Box 1).1–4 The immense psychological impact of psoriasis is often underestimated by healthcare professionals and attention to this should form the cornerstone of the consultation.1

Box 1: Patient history

History should cover:1–4

  • first appearance of the disease. Does it settle and then recur, and over what period of time?
  • family history
  • current medication—did the psoriasis start after commencing a new drug (e.g. lithium, beta blockers, angiotensin-converting enzyme inhibitors, or chloroquine)
  • any recent stress that the patient may be under
  • whether the patient has had a recent streptococcal sore throat as this may trigger guttate psoriasis
  • treatment history—record what treatment has been used, where, for how long, and the result. Assess whether previous treatments have been used optimally*
  • psychological impact—this could be assessed by the Dermatology Life Quality Index (a simple 10-question validated questionnaire)
*It should be noted that some of the topical treatments are messy and difficult to apply. Many patients will hope to see a rapid improvement, but it can take a few weeks for the skin to improve, and it often does not return to normal but remains red (but is flat and not scaly). In this situation patients can feel that the treatment has failed, when it has already had its maximum effect.

Types of psoriasis

Psoriasis can affect all areas of the skin and presents in different ways depending on the site:

Plaque psoriasis—around 80% of patients with psoriasis have plaque psoriasis; the lesions are symmetrical, bright red, and very scaly. They tend to occur on extensor surfaces, typically the elbows, knees, and buttocks.5

Guttate psoriasis—this is characterised by smaller lesions (?1 cm) that occur in large numbers on the trunk and limbs. Streptococcal sore throats are an important trigger, but small plaque psoriasis can also occur spontaneously.2,4

Flexural psoriasis—this occurs in skin folds, armpits, under the breasts, between the buttocks, and in the groin area. The moistness of the site significantly reduces the surface scale. The skin has a glazed appearance and may feel tight and sore.6

Scalp psoriasis—thick scales and redness that may also be obvious around the scalp margins, on the forehead, neck and behind the ears.6

Nail psoriasis—this causes pitting, subungual hyperkeratosis (thickened scale under the distal part of the nail),7 and may lead to onycholysis (the nail lifts away from the nail bed).4

Hand and foot psoriasis—this causes scaling, fissuring, and erythema, which can be difficult to differentiate from eczema. A well-demarcated edge suggests psoriasis; vesicles imply pompholyx eczema.8

Palmaplanter pustular psoriasis—this is a type of hand and foot psoriasis. It is characterised by pustules on the palms and soles of feet. The pustules gradually develop into circular, brown, scaly spots, which then peel off. The pustules may reappear every few days or weeks.4

Treatment options

Many patients with psoriasis can be successfully treated in primary care. Healthcare professionals should provide patients with education and support on the use of treatments, expected results, and potential side-effects.1 Patients may need a range of agents for different body sites; if they are paying for prescriptions, a prepaid 3- or 12-month prepayment certificate is probably advisable.

Plaque psoriasis
Topical treatment is a practical option if up to 10%–15% of the body area is involved.5 The area of a flat hand with fingers closed together represents approximately 1% of the body surface area.9 The size of the plaques also affects the choice of treatment: it is impractical to prescribe a treatment that should only be applied to the plaques themselves if they are small but numerous. For all patients an emollient is advisable to soften the scale, relieve itch, and aid penetration of other agents. Prescribe a cream that should be applied 2–3 times a day (500 g usually on a repeat prescription). The patient should also have a special emollient for use in the bath/shower.

The sequence of choice for treatment of psoriasis will depend on the extent and pattern of psoriasis, and patient preference.1

Vitamin D analogues (calcipotriol, calcitriol, tacalcitol)
Calcipotriol (cream or ointment) is the most effective of the three available options for plaques, and has become one of the first-line treatments.10 It should be applied to the plaque in a fairly thick layer, once or twice daily. Improvement usually becomes apparent within 2 weeks and continues for at least 8 weeks, at which point, some patients are clear but most reach a plateau—this is often very minimal scale but residual erythema. If treatment is continued, but at a reduced frequency, the improvement can often be maintained. The main side-effect is skin irritation (more likely with ointment), but this may settle with time so patients should be encouraged to continue. The maximum dose per week for adults is 100 g and it can be used long term. Calcitriol and tacalcitol are less irritant than calcipotriol and may be more suitable for the face or flexures. Rates of application should be limited to 30 g per day for calcitriol and 10 g per day for tacalcitol.10

Calcipotriol with betamethasone dipropionate
Calcipotriol/betamethasone dipropionate ointment is an effective but relatively costly treatment. There are concerns over the use of a potent topical steroid for psoriasis, including the risk of rebound exacerbation when treatment is discontinued and the possibility of absorption and consequent systemic effects. The ointment can be used in the management of large plaque psoriasis where calcipotriol has failed.1 It is applied once daily to a maximum of 30% of the body surface for a maximum of 4 consecutive weeks, no more than 15 g daily, 100 g per week. If, on review, the psoriasis has improved, a useful compromise is to switch to calcipotriol for 4 weeks and alternate the two products; this will help to minimise side-effects.10

Alternative treatment options

  • Salicylic-acid-containing preparations—these can help heavily scaled plaques and are particularly useful for the hands, feet, and scalp.2 There are various proprietary products containing refined coal tar, which although less effective than crude coal tar, are more acceptable to the patient. A coal tar lotion can be a way of treating multiple small plaques (including guttate psoriasis) as the treatment can be applied to diseased and normal skin. Unwanted effects include odour, which some patients find unacceptable, mild irritation, and increased sensitivity to sunlight11
  • Tazarotene—this vitamin A gel can be applied once daily to patches of psoriasis affecting a body surface area of up to 10%. Local irritation is a common side-effect. As it is potentially teratogenic, women should not become pregnant while using this treatment and it should not be used during pregnancy or breastfeeding10
  • Dithranol—the use of dithranol in a ‘short-contact’ regimen is advised and is very effective for accessible localised psoriasis in motivated patients. This regimen involves applying high concentrations of dithranol (1%–10%) for 15–30 minutes daily followed by washing off, which allows sufficient dithranol to remain fixed to the plaques for a clinical effect to be obtained without the need for special dressings. Patients should be warned that dithranol will stain the skin, hair, and fabrics.10 Despite this, I believe that dithranol has a valuable role for selected patients who can devote time to treating their disease.

 

Guttate psoriasis
Guttate psoriasis is self limiting and often resolves spontaneously. Topical tar extracts and an emollient may be beneficial. Vitamin D analogues can be helpful but may be time consuming to apply and therefore not practical. Reassure the patient that the lesions will almost certainly resolve spontaneously. If they fail to do so, a short course of ultraviolet B phototherapy may be required.12 Although both long-term antibiotics and tonsillectomy have frequently been advocated for patients with recurrent guttate psoriasis or chronic plaque psoriasis, there is no good evidence that either intervention is beneficial.13

Flexural psoriasis
Tacalcitol or calcitriol can be effective for flexural psoriasis and can be combined with a mild or moderately potent topical steroid (e.g. clobetasone butyrate cream) using each therapy once daily (e.g. one in the morning and one at night). The risk of atrophy is significant in flexural skin, so the frequency of application of a topical steroid should be reduced when the skin has improved. Patients need to be aware that the creams are controlling the disease, and it may recur if they stop using them; control can be maintained by reduced frequency of applications.

An antifungal/corticosteroid combination can be beneficial if a yeast or fungal superinfection is suspected.8

Scalp psoriasis
The treatment of scalp psoriasis can be challenging, particularly if severe. The Psoriasis Association has provided advice on how to apply treatments, depending on severity, which may be useful for patients (www.psoriasis-association.org.uk/scalp.html):

  • Mild—a tar-based shampoo used at least twice a week may be adequate
  • Moderate—a tar-based shampoo followed by calcipotriol or betamethasone scalp application applied daily and left on the scalp skin2
  • Severe (very thick adherent scale and soreness)—a coal tar/salicylic acid combination should be applied to the scalp and left on overnight.1 This is to soften the scale. The hair should then be washed in the morning with a tar shampoo and the scalp combed to remove the softened scale. Once the scale has been cleared (7–10 days) the patient can stop using the keratolytic agent. The next stage, after washing, is to apply a topical steroid (e.g. betamethasone/mometasone scalp application). These often sting when applied. As the psoriasis gradually improves, the frequency of applications of treatments can be reduced. A vitamin D analogue can provide a safe maintenance treatment when long-term therapy is required.14

Two newer preparations that are also available include a calcipotriol/betamethasone combination (to be applied at night and washed out the following morning) and a clobetasol short-contact shampoo (applied to the scalp for 15 minutes when the hair is dry, and then washed out) for moderate psoriasis.10

Psoriasis affecting the scalp margins can be treated using a gentler vitamin D analogue (e.g. tacalcitol) alternating with a mild to moderately potent topical steroid as suggested for flexural psoriasis.14

Nail psoriasis
There is no reliable effective treatment for nail psoriasis.2 Advice about camouflage with nail varnish for female patients may be helpful. Systemic treatment (e.g. methotrexate) prescribed for resistant or more severe disease may improve the nails.

Hand and foot psoriasis
Psoriasis affecting the hands and feet can be difficult to treat and may require input from secondary care. Initial management would include use of:

  • an emollient—as often as required and for washing.1 Avoid soaps, detergents, and household/occupational irritants. A thicker emollient, although potentially less acceptable, may be more beneficial. A urea-containing cream softens scale more effectively
  • a keratolytic agent—will help to soften thick scale (e.g. salicylic acid ointment BP applied twice a day)1
  • topical steroids—potent or very potent preparations and an ointment rather than cream penetrates more effectively.1 Occlusion under plastic gloves at night can also aid penetration. A steroid/salicylic acid combination will help to soften the scale and treat the disease
  • vitamin D analogues—these have a useful steroid-sparing effect.1 These have limited efficacy as they should be applied in a thick layer, which is impractical for hands and feet.

Reassure patients that small pustules of palmaplantar pustular psoriasis do not signify infection and that the disease cannot be transmitted.

Second-line treatments

For many patients, the correct use of topical treatment regimens will result in effective control. Psoriasis may also settle spontaneously and remain dormant for a while. However, a significant number of patients may require treatment that can only be accessed through secondary care. These are summarised below:

Ultraviolet phototherapy
Psoriasis can be treated with ultraviolet (UV) phototherapy in the form of narrowband UVB for plaque psoriasis or PUVA (UVA and topical or oral psoralen) for hand and foot psoriasis. Patients will have an initial assessment for an explanation of the regimen, possible side-effects, safety precautions, and to determine if the patient is taking any medication that could cause photosensitivity. Treatment takes place in a hospital dermatology department, 2–3 times a week, for about 6 weeks. The skin is monitored at each visit and dosage is adjusted accordingly. Topical PUVA is used to treat small areas of affected skin (e.g. hands and feet). Topical psoralen can be applied to the lesions or they can be soaked for 15 minutes in a psoralen solution prior to UVA exposure.15 The mean remission length is 6 months.

Methotrexate
Methotrexate is used in the treatment of severe resistant psoriasis.1 The most important potential side-effect is acute marrow suppression; it is also teratogenic, and care must be taken when co-prescribing with other drugs. Full blood count, plasma urea, electrolytes and creatinine, and liver enzyme tests should be monitored closely during treatment.16

Acitretin
Acitretin is a retinoid, which is particularly effective for the treatment of palmoplantar pustular psoriasis.5,14 It is teratogenic and women should avoid conceiving during treatment and for 2 years after taking it. Side-effects include dryness of the mucous membranes, abnormalities of serum lipids and rarely hepatitis.17 Liver function tests and lipid profiles should be monitored prior to and during treatment.15

Ciclosporin
Ciclosporin is an immunosuppressant licensed for the treatment of severe psoriasis. The main side-effects are nephrotoxicity, hypertension, and gingival hyperplasia.1 Blood pressure and renal function should therefore be monitored every 2 weeks for the first 3 months, and then every 2 months if they are satisfactory. Blood pressure and renal function should be monitored fortnightly during dose titration and after achieving stable dose and then monthly.18

Alternative agents
There are a number of other agents that can also be used to treat psoriasis including:1

  • azathioprine
  • hydroxycarbamide
  • mycophenolate mofetil.

Biological agents

Biological agents are third-line therapeutic options for psoriasis for patients in whom topical and systemic treatments have not proven effective. Adalimumab, etanercept, and infliximab have all been approved by NICE for treatment of plaque psoriasis if: the condition has not responded to standard systemic therapies including ciclosporin, methotrexate, and PUVA (psoralen and long-wave ultraviolet radiation); or the person is intolerant of, or has a contraindication to, these treatments.19–21 Efalizumab was also approved by NICE, but it has since had its marketing authorisation suspended. To qualify for treatment with these biological agents, the patient must also have severe psoriasis as defined by the Psoriasis Area Severity Index (PASI) and the Dermatology Life Quality Index (DLQI); the criteria for eligibility are shown in Table 1. Treatment with etanercept, infliximab, or adalimumab should only continue if an adequate response is shown after the specified treatment duration (see Table 1).

Key features of the biological agents include the following:22

  • Prescription of these treatments should only be initiated by consultant dermatologists
  • They are given by injection (either at surgery or home depending on which agent)
  • Treatment schedules and frequency vary
  • They will improve psoriasis for some patients but not all
  • Short-term side-effects are generally minor although an allergic reaction to the injection can occur
  • Long-term safety is still being evaluated
  • These agents are expensive (between £8,000 and £10,000 per annum)
  • They must be taken continuously to maintain improvement.

Table 1: Criteria required to be eligible for treatment with etanercept, infliximab, or adalimumab19–21

Therapy* Severity of disease (criteria for both PASI and DLQI must be fulfilled) When to assess response Adequate response
PASI DLQI

Adalimumab

?10

>10

16 weeks

  • a 75% reduction in the PASI score (PASI 75) from when treatment started
or
  • a 50% reduction in the PASI score (PASI 50) and a five-point reduction in DLQI from start of treatment

Etanercept

?10

>10

12 weeks

Infliximab

?20

>18

10 weeks

*Patients may be eligible for these therapies if the psoriasis has not responded to standard systemic therapies including ciclosporin, methotrexate and/or PUVA (psoralen and long-wave ultraviolet radiation); or the person is intolerant of, or has a contraindication to, these treatments
PASI=Psoriasis Area Severity Index; DLQI=Dermatology Life Quality Index

Conclusion

This article aims to provide practical advice on the management of psoriasis, which is supported by recommendations from the British Association of Dermatologists (BAD) guideline and other sources. In the first instance, patients with psoriasis will generally consult a GP for advice and guidance. There are numerous effective treatment options available and it is important to spend time educating the patient about the correct use of treatments in order to maximise the benefit from the prescribed regimen. If the patient’s response to treatment is suboptimal, they should be referred to secondary care for access to a wider range of more powerful therapeutic options.

The psychological burden of psoriasis on the patient’s day-to-day life, should always be explored and support offered.Patient support groups and dermatology related organisations are very useful for providing patient information. These include:

References

  1. British Association of Dermatologists. General management of psoriasis—recommendations. www.bad.org.uk/site/1113/default.aspx (accessed 18 August 2009).
  2. British Association of Dermatologists. Psoriasis—an overview. www.BAD.org.uk/site/864/default.aspx (accessed 18 August 2009).
  3. Primary Care Dermatology Society. Diagnosing skin disease: history. www.pcds.org.uk/diagnosing-skin-disease/history (accessed 18 August 2009).
  4. NHS Clinical Knowledge Summaries. Patient information leaflet: psoriasis. www.cks.nhs.uk/patient_information_leaflet/Psoriasis (accessed 18 August 2009).
  5. Wong C, Kirby B. Current treatments in the management of psoriasis. Prescriber. April 2003; 53–60.
  6. The Psoriasis Association. Scalp psoriasis. www.psoriasis-association.org.uk/scalp.html (accessed 1 September 2009).
  7. DermNet. Nail psoriasis. dermnetnz.org/scaly/nail-psoriasis.html (accessed 1 September 2009).
  8. Berth-Jones J. Regional psoriasis. Dermatology in Practice 2001; 9 (5).
  9. Habif T. Clinical dermatology. St. Louis: The CV Mosby Company, 1990; p 900.
  10. British Association of Dermatologists. Topical vitamin D. www.bad.org.uk/site/1116/default.aspx (accessed 18 August 2009).
  11. British National Formulary. BNF 57. London: Royal Pharmaceutical Society, 2009.
  12. British Association of Dermatologists. Phototherapy. www.bad.org.uk/site/1120/Default.aspx (accessed 24 August 2009).
  13. Owen C, Chalmers R, O’Sullivan T, Griffiths C. Antistreptococcal interventions for guttate and chronic plaque psoriasis. Cochrane Database Syst Rev 2000; (2): CD001976.
  14. British Association of Dermatologists. Specific sites. www.bad.org.uk/site/1119/Default.aspx (accessed 24 August 2009).
  15. British Association of Dermatologists. Treatments for moderate or severe psoriasis. www.bad.org.uk/site/866/Default.aspx (accessed 24 August 2009).
  16. British Association of Dermatologists. Methotrexate. www.bad.org.uk/site/1121/Default.aspx (accessed 24 August 2009).
  17. British Association of Dermatologists. Oral retinoids. www.bad.org.uk/site/1122/Default.aspx (accessed 24 August 2009).
  18. British Association of Dermatologists. Ciclosporin. www.bad.org.uk/site/1123/Default.aspx (accessed 24 August 2009).
  19. National Institute for Health and Care Excellence. Adalimumab for the treatment of adults with psoriasis. Technology Appraisal 146. London: NICE, 2008. Available at: www.nice.org.uk/guidance/TA146
  20. National Institute for Health and Care Excellence. Etanercept and efalizumab for the treatment of adults with psoriasis. Technology Appraisal 103. London: NICE, 2006. Available at: www.nice.org.uk/guidance/TA103
  21. National Institute for Health and Care Excellence. Infliximab for the treatment of adults with psoriasis. Technology Appraisal 134. London: NICE, 2008. Available at: www.nice.org.uk/guidance/TA134
  22. The Psoriasis Association. Biological drugs for the treatment of psoriasis. www.psoriasis-association.org.uk/biologics.html (accessed 24 August 2009). G
  • The treatment of psoriasis can be quite complicated as there are now many therapies available
  • A locally agreed care pathway or algorithm could help improve care and reduce unnecessary referrals to specialist services
  • Additional GPwSIs or specialist nurses could be employed in the community to help manage patients and educate GPs
  • There is no mandatory tariff for dermatology services so PCTs and PBC consortia could negotiate such services to be provided from the local acute trust but at reduced cost or even a ‘block contract’
  • This option appears attractive as it allows consultant supervision to identify the patients who need biological or cytotoxic therapies