Guidelines for the management of psoriasis

This document incorporates and summarises recently published Australian consensus treatment goals [1] and guidelines published by the British Association of Dermatologists [2,3], American Academy of Dermatology [4-7] and NICE [8]. It is relevant to the treatment of psoriasis in New Zealand.

Definition

Psoriasis is a chronic inflammatory skin disease that is characterised by disfiguring, scaling and erythematous plaques that may be itchy and/or painful. Although once thought of as a benign dermatological condition with few serious complications, moderate-to-severe psoriasis is now considered a multisystem disease that is associated with, or increases, the risk of other comorbidities. Psoriasis can be both emotionally and physically debilitating and impact on quality of life significantly.

Background

• In New Zealand psoriasis affects about 2–3% of the population. This is comparable to worldwide figures collected by the World Psoriasis Day consortium.
• Different rates of psoriasis are seen in certain ethnic groups; higher in Northern Europeans and lower in Australian aborigines. Very little data exists on the prevalence in New Zealand Mãori.
• Onset can occur at any age, but two peaks in incidence have been identified – one in the late teens, and the other between 50–60 years old.
• There is a genetic predisposition with about one third of patients reporting to have an affected relative.
• Approximately 80% of patients affected with psoriasis have mild to moderate disease.
• Psoriasis tends to run a chronic course, with remissions and exacerbations.
• Up to 40% of people with skin psoriasis have some signs of psoriatic arthritis.
• Metabolic syndrome, a condition involving obesity, hyperlipidaemia, hypertension and insulin resistance is commonly found in patients with psoriasis, and significantly increases the risk of developing cardiovascular morbidity and mortality.
• Severe psoriasis, particularly in younger patients, is an independent risk factor for myocardial infarction.
• Psoriasis is associated with depression and substance abuse, including alcohol.

Patient assessment and diagnosis

The diagnosis and assessment of psoriasis and its extent and severity is based on:

• Objective assessment of the body surface area (BSA) involvement, disease location, thickness and symptoms, presence or absence of psoriatic arthritis, and any associated comorbidities.

With

• Subjective assessment of the physical, psychological, social, and financial impact of the disease on the patient’s life.

Definition of plaque psoriasis severity

To improve patient care, both the European and Australian consensus programme have been established to develop specific treatment goals for psoriasis. In doing this, the need for defining psoriasis severity was evident. A summary of the Australian consensus for a definition of plaque psoriasis severity is shown below.

Referral to specialist

Referral to a specialist is recommended in the following circumstances:

• Diagnostic uncertainty
• Acute erythroderma or generalised pustular psoriasis (emergency referral) or acute unstable psoriasis (urgent referral)
• Difficult to treat sites (e.g. face, genitalia, palms and soles) unresponsive to initial treatment
• Extensive disease (more than 10–20% BSA involvement) likely to require phototherapy and/or systemic treatment
• Psoriasis unresponsive to topical therapies
  • Failure of appropriately used topical therapy for a reasonable period (e.g. 2–3 months)
  • Unexpected adverse reactions to topical therapies
  • Need for increasing amounts or potency of topical steroids
• Major physical and/or psychological disability associated with the disease

Management and treatment

There is no cure for psoriasis. Successful management is very much dependent on the patient fully understanding the chronic nature of psoriasis and the therapeutic options that are available to them. Points to consider prior to initiating therapy include:

• Reassuring the patient that psoriasis is not contagious.
• Determining how the patient perceives their disability as this will often dictate the need and type of treatment.
• Educating patients about various treatments and how some can be difficult to use and how some may have adverse effects.
• Provide general advice regarding the benefits of not smoking, avoiding excessive alcohol and maintaining optimal weight.

Treatment must be individualised and depends on the characteristics of the psoriasis – its body location, thickness of lesions and degree of erythema and scaling. In addition, the patient’s preference or commitment to therapy must also be considered.

To enhance the availability and appropriate use of therapies and increase patient satisfaction, psoriasis treatment goals have been developed by both European and Australian consensus committees. The Australian treatment goals, which are in agreement with the European treatment goals, are summarised in the following table.

The guidelines above provide a framework for initiating and monitoring psoriasis treatment, however there needs to be some flexibility in how they are used in clinical practice. Even though the guideline may indicate modifying or changing your patient’s treatment according to their assessments, there are situations where a treatment change is not actually necessary. Some points to consider are:

Although a high DLQI >10 and a low PASI ≤10 can be considered

• moderate to severe disease, the high DLQI may be a result of other factors other than the psoriasis itself. These may include:
  • Co-morbid conditions or psychiatric issues
  • Patient has unrealistic expectations of treatment (especially if consistently high DLQI despite reducing PASI scores)
  • Significant life changing event or serious illness that may temporarily worsen DLQI and/or PASI scores
• Treatment success or failure is dependent on how the patient perceives their condition and how committed they are to their treatment regimen. It is very important to incorporate patients’ wishes in treatment decisions. For example, a patient with satisfactory response to treatment may wish to change their treatment for various reasons, even though this may be contrary to the treatment guidelines.

The American Academy of Dermatology's position statement on the treatment of patients with moderate to severe psoriasis is as follows:

Therapeutic options in the treatment of chronic plaque psoriasis should be tailored to meet individual patients’ needs. Psoriasis patients with moderate-to-severe psoriasis and thus, candidates for systemic therapy, should be placed on the appropriate therapy from the beginning, i.e. phototherapy, or systemic therapy including biologic therapy. The old paradigm of “stepwise-therapy”, i.e. first phototherapy, then oral systemic therapies and finally biologic therapies in ascending order is not required. The decision for treatment should be based on efficacy, potential adverse effects, prior treatments, patient preference, duration and severity of disease, medical risk factors, co-morbidities, and potential impact on quality of life.

Pharmacological therapy in psoriasis

Topical therapy

Approximately 80% of psoriasis patients have mild to moderate disease that can be treated with topical agents. Successful treatment is highly dependent on patient acceptance of their topical regimen. It is important to match patient expectations with practical considerations. General principles for using topical therapies include:

• Choice of vehicle – multiple vehicle types available to deliver the active agent. These can include ointments, creams, solutions, gels, foams, sprays, shampoos, oils and lotions. The vehicle used may have an effect on the efficacy of the active agent but the optimal choice is usually dictated by what the patient feels most comfortable using.
• Occlusion of some topical agents can change the effectiveness of the medication. For example, some topical corticosteroids when occluded have much greater penetration, thereby varying effectiveness.
• Compatibility issues when using a combination of topical agents. For example, calcipotriol should not be used concurrently with agents that alter the pH of its base, such as topical lactic acid or salicylic acid. Patients may be advised to apply various topical medications at different times throughout the day.
• Review patients regularly – those who require continuous topical treatment should be monitored and treatment adjusted so they receive the least potent agent or agent with lowest long-term risk that achieves disease control.

Topical treatments include emollients, vitamin D analogues, corticosteroids, salicylic acid, retinoids, coal tar and dithranol. The following table summarises the main topical treatment options.

Phototherapy

• Traditional broadband ultraviolet B (BB-UVB) phototherapy has been used to treat psoriasis for more than 75 years. In the last 20 years, narrowband UVB lamps have improved phototherapy for psoriasis with increased efficacy and reduced toxicity.
• Photochemotherapy (PUVA) was introduced to New Zealand in the 1980s but is now rarely used.
• Phototherapy can be given either as monotherapy or in combination with topical or systemic agents.
• Initial dosage of UVB is based according to Fitzpatrick skin type or the minimal erythema dose (MED), with subsequent dosages adjusted accordingly.
• Phototherapy is administered in hospital or some private dermatological practices. It requires treatments 2-3 times per week for up to 2 months or longer.
• Risks of phototherapy include erythema and burning, premature aging of the skin, and presumed increase in skin cancer. Accurate records of the dosage and number of treatments along with any side effects must be recorded for every patient.
• Phototherapy is contraindicated in patients with known lupus erythematosus or xeroderma pigmentosum.

Traditional (non-biologic) systemic therapy

• Most commonly used traditional systemic agents include methotrexate, ciclosporin, and acitretin. Their oral route of administration and low cost (compared with biologics) makes them important treatment options.
• Methotrexate given as a single weekly oral dose (range 10 to 30mg) is effective for at least 60% of psoriasis patients. It is contraindicated in pregnancy and lactation, in patients with cirrhosis, and in patients with significant anaemia, leucopenia or thrombocytopenia. Patients require ongoing monitoring to reduce the risk of haematological toxicity and hepatotoxicity.
• Ciclosporin is highly effective as it produces a rapid response. Useful in crisis management when rapid or short-term disease control is required, e.g. psoriasis flare. Patients must be monitored for nephrotoxicity and hypertension.
• Acitretin, an oral retinoid agent, is particularly useful for erythrodermic and pustular forms of psoriasis. It is considered the treatment of choice in HIV-positive patients with severe psoriasis as it does not cause significant immunosuppression. It is highly teratogenic, so is contraindicated in pregnancy and its use is severely limited in women of childbearing age (strict contraception for 2 years after stopping treatment).
• Other systemic agents include azathioprine, fumaric acid esters, hydroxyurea, leflunomide, mycophenolate mofetil, sulfasalazine, tacrolimus, and 6-thioguanine. These agents may be considered in treatment-resistant disease or where multiple adverse events prevent or limit the use of methotrexate, ciclosporin and acitretin.

Biologic systemic therapy

In the last decade biologic response modifiers in the treatment of psoriasis have been showing promising results, treatment is well tolerated and often very effective in moderate to severe disease. While they are often more efficacious than traditional systemic therapies, the long term risks are still largely unknown. In addition, biologic systemic therapy is expensive, hence their use in clinical practice remains limited.

In most countries where biologic response modifiers are being used to treat severe chronic plaque psoriasis or psoriatic arthritis, fully funded access to these agents is controlled by exclusion and inclusion criteria set by government medical agencies. PHARMAC, the governing agency in New Zealand, require patients to meet the following criteria to receive fully funded systemic therapy with adalimumab, etanercept, and infliximab.