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Guidelines for the management of psoriasis

Author: Vanessa Ngan, Staff Writer; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, March 2014.

Guidelines for the management of psoriasis — codes and concepts

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.


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.


  • 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.


  • Subjective assessment of the physical, psychological, social, and financial impact of the disease on the patient’s life.
Objective assessments
Psoriasis features and symptoms
  • Chronic plaque psoriasis usually presents as red, scaly patches of skin with very well defined edges.
  • The scale is typically silvery white, unless psoriasis is affecting body folds, in which case scaly patches may be smooth and shiny.
  • Extensor surfaces most often affected, and scalp involvement is common.
  • Fissures in the skin crease may occur in flexural psoriasis.
  • Nail involvement shows pitting, onycholysis and subungual hyperkeratosis.
  • Other less common forms of psoriasis to be aware of include those involving the palms, soles, and intertriginous areas, and pustular and erythrodermic psoriasis.
  • Systemic symptoms including fever and malaise may be indicative of unstable forms of psoriasis such as erythrodermic or generalised pustular psoriasis.
Psoriasis severity

Severity is determined using one or more of the following assessment tools.

  • PGA – Physicians/Patients Global Assessment: severity is estimated by both clinician and patient using a static global assessment score, which uses the descriptions “clear”, “nearly clear”, “mild”, “moderate”, “severe” or “very severe”.
  • BSA – Body Surface Area: severity is defined by how much of the body surface area is affected.
    • Mild psoriasis: <5% of BSA
    • Moderate psoriasis: 5-10% of BSA
    • Severe psoriasis: >10% of BSA
    (Note: 1% of BSA is approximately equal to the palm of the patient’s hand, excluding fingers)
  • PASI – Psoriasis Area and Severity Index: measure of overall severity and extent of psoriasis by assessing BSA and intensity of redness, thickness and scaling. A single score is calculated and ranges between 0 (no disease) to 72 (maximal disease). Commonly used in clinical trials for psoriasis treatments and by dermatologists and clinicians working in specialised treatment centres.
Presence of psoriatic arthritis
  • Detection of psoriatic arthritis is based on symptoms, examination of skin and joints and compatible radiological findings.
  • Available validated tools to assess adults for psoriatic arthritis (all patient-completed questionnaires) include:
    • PEST – Psoriasis Epidemiology Screening Tool
    • ToPAS – Toronto Psoriatic Arthritis Screen
    • PASE – Psoriatic Arthritis Screening Evaluation
Presence of co-morbidities
  • Identify co-morbidities by taking a complete medical history and physical examination, including
    • Blood pressure measurement
    • BMI calculation
    • Diabetic assessment (e.g. fasting glucose and lipids, retinal screening)
    • Cardiovascular assessment (e.g. electrocardiogram, validated risk estimation tools)
Subjective assessments
Assess impact of psoriasis on physical, psychological, and social wellbeing. Questions to ask include:
  • How does having psoriasis affect the patient’s daily life, at home, work or school?
  • How is the patient coping with the condition and are they using any treatments?
  • How does the patient feel – e.g. depressed, anxious, low self-esteem, lonely?
  • How is the condition affecting their relationship with their partner, family, friends etc?
  • Do they need further advice and support?
Quality of Life (QOL) measurements are important to properly assess the full effect of an illness such as psoriasis on patients. Two dermatology specific tools to assess QOL impact of psoriasis are:
  • DLQI – Dermatology Life Quality Index: a self-reported questionnaire that consists of 10 items covering symptoms and feelings, daily activities, leisure, work and school, personal relationships and treatment. Each item is scored on a four-point scale, with higher scores indicating greater impairment in QOL. A final score is calculated and ranges from 0 (no impairment of QOL) to 30 (maximum impairment).
  • SKINDEX-16 – Single-page survey that evaluates the most bothersome rather than the most frequent symptoms. The self-reported survey measures cognitive effects, social effects, depression, fear, embarrassment, anger, physical discomfort and physical limitations.

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.

Definition of plaque psoriasis severity: An Australian consensus
Mild plaque psoriasis
  • PASI ≤10 and DLQI ≤10
Moderate to severe plaque psoriasis
  • PASI >10 irrespective of DLQI (i.e.: a PASI >10 is considered moderate to severe disease regardless of the DLQI)
  • PASI ≤10 and DLQI >10 – presence of one or more of the following features may significantly impair quality of life in setting of mild psoriasis and alter classification to moderate to severe disease
    • Involvement of visible areas, major parts of the scalp, genitals, or palms and/or soles
    • Onycholysis or onychodystrophy of at least two fingernails
    • Pruritus leading to excoriation

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.

Psoriasis treatment goals for mild plaque psoriasis
PASI ≤10 and DLQI ≤10
  • Treat with topical agents
  • Remains mild, continue with topical agents
  • Worsening condition, treat as for moderate/severe psoriasis
Psoriasis treatment goals for moderate to severe plaque psoriasis
PASI >10 or PASI ≤10 and DLQI >10
  • Treat with non-biologic systemic therapy and/or phototherapy
Response (measured by percentage change in PASI score)*
Good =
∆ PASI ≥75% and DLQI ≤5
  • Continue with systemic therapy and/or phototherapy
Partial =
∆ PASI ≥50% and <75%
  • And DLQI ≤5, continue with systemic therapy and/or phototherapy
  • And DLQI >5, modify/change therapy**
Failed =
∆ PASI <50
  • Modify/change therapy**
  • If at least 2 of 4 therapies trialed or contraindicated, and PASI and/or DLQI remain > 10, treat with biologic therapy
*% change in PASI score compares PASI score at treatment initiation to PASI score at treatment review. Appropriate time to review varies with each treatment and the range is 6–24 weeks.
** In addition to changing treatment, modify may include adding topicals or other systemic treatments, increasing dose/frequency, or hospital admission. Patient’s wishes should be taken into account in treatment decisions.

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.

Topical treatmentFeatures
  • Helps to lift scale and reduce fissuring.
  • Use as a soap substitute where soap is especially irritating to inflamed skin.
  • Some patients don’t like the greasy feel of certain products.
Coal tar
  • Used for over 100 years to treat psoriasis and is safe and effective.
  • Limited use because of poor patient acceptance due to cosmetic issues such as smell, staining of skin and clothes, messy to apply and potential to cause folliculitis.
  • Effective on large, thick plaques as ‘short-contact therapy’ where it is applied then rinsed off with water after a short period of time (10 to 30 minutes).
  • Often irritant to surrounding normal skin and may stain skin and clothing.
Salicylic acid
  • Effective keratolytic agent that reduces scaling to allow other topical treatments to penetrate.
Vitamin D analogue (calcipotriol)
  • Effective on most chronic plaque psoriasis. Initially use twice daily and reduce to once daily as condition improves.
  • Ointment base is better absorbed than cream base.
  • Can cause irritation, especially on the face and in flexures.
  • Rarely causes elevated serum calcium. To avoid risk of hypercalcaemia, do not use with calcium or vitamin D supplements.
  • Total dose should not exceed 5 mg/week (i.e. 100 g of 50 mcg/g ointment or cream).
  • Often used in combination with corticosteroid agent as it has a corticosteroid-sparing effect.
  • Use in combination with salicylic acid can reduce efficacy of calcipotriol.
  • Cornerstone of treatment for most patients, especially those with limited disease. Easy to use and causes no irritation.
  • Use mild to moderate potency corticosteroid once or twice daily on the face, intertriginous areas, areas with thin skin, and in infants (for a maximum of 2 weeks). If response unsatisfactory consider using a topical calcineurin inhibitor.
  • Initial therapy with moderate to high potency corticosteroids can be used in other areas of the body (trunk, limbs and scalp). Apply once daily for up to 4 weeks. Consider combining with other topical agents, UV light, and systemic agents if response unsatisfactory.
  • Thick chronic plaques and plaques on hands and feet may require very high potency agents (class I steroids) for 2-4 weeks. Do not exceed 50 g/week.
  • Potential side effects that limit use include local effects such as skin atrophy, telangiectasia, striae, acne, and folliculitis. Systemic effects include adrenal suppression, increased intraocular pressure, glaucoma, and cataracts.
  • Tachyphylaxis may occur with long-term use and results in decreased efficacy, and sometimes an acute flare-up when treatment is stopped.
  • Minimise side effects and tachyphylaxis by gradual reduction in frequency, or change to less potent formulation following clinical response. Another strategy is to have corticosteroid-free times, for example, take a minimum break of 4 weeks before reusing high potency topical corticosteroids.
Calcineurin inhibitor (tacrolimus, pimecrolimus)
  • Initiated by dermatologist or doctor with expertise in treating psoriasis.
  • Effective in facial and intertriginous psoriasis and may be preferable to long-term potent topical steroids in these sites.
  • Apply twice daily for up to 4 weeks, then review treatment.
  • Most common side effect is burning and itching that generally reduces with ongoing usage.
  • Tacrolimus is not availablle in New Zealand (2014).
Retinoid (tazarotene)
  • Best used in combination with topical corticosteroids. Applied once daily.
  • Most common side effect is skin irritation in lesional and perilesional skin.
  • Potentially photosensitizing so use with caution when combining with phototherapy.
  • Tazarotene is not available in New Zealand.


  • 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.

PHARMAC Initial application to use adalimumab, etanercept, and infliximab.
Patient must meet all of the following criteria…..
  1. Either:
    1. Patient has "whole body" severe chronic plaque psoriasis with a Psoriasis Area and Severity Index (PASI) score of greater than 15, where lesions have been present for at least 6 months from the time of initial diagnosis; OR
    2. Patient has severe chronic plaque psoriasis of the face, or palm of a hand or sole of a foot, where the plaque or plaques have been present for at least 6 months from the time of initial diagnosis; AND
  2. Patient has tried, but had an inadequate response (see Note) to, or has experienced intolerable side effects from, at least three of the following (at maximum tolerated doses unless contraindicated): phototherapy, methotrexate, cyclosporin, or acitretin; AND
  3. A PASI assessment has been completed for at least the most recent prior treatment course (but preferably all prior treatment courses), preferably while still on treatment but no longer than 1 month following cessation of each prior treatment course; AND
  4. The most recent PASI assessment is no more than 1 month old at the time of application.
Note: “Inadequate response” is defined as: for whole body severe chronic plaque psoriasis, a PASI score of greater than 15, as assessed preferably while still on treatment but no longer than 1 month following cessation of the most recent prior treatment; for severe chronic plaque psoriasis of the face, hand or foot, at least 2 of the 3 PASI symptom subscores for erythema, thickness and scaling are rated as severe or very severe, and the skin affected is 30% or more of the face, palm of a hand or sole of a foot, as assessed preferably while still on treatment but no longer than 1 month following cessation of the most recent prior treatment.

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Related information



  1. Baker C, Mack A, Cooper A, Fischer G, Shumack S, Sidhu S, Soyer P, Wu J, Chan J, Nash P, Rawlin M, Radulski B, Foley P. Treatment goals for moderate to severe psoriasis: an Australian consensus. Australas J Dermatol. 2013 May;54(2):148-54
  2. Cohen SN, Baron SE, Archer CB; British Association of Dermatologists and Royal College of General Practitioners. Guidance on the diagnosis and clinical management of psoriasis. Clin Exp Dermatol. 2012 May;37 Suppl 1:13-8
  3. Smith CH, Anstey AV, Barker JNWN, et al. British Association of Dermatologists'; guidelines for biologic interventions for psoriasis 2009. British Journal of Dermatology 2009;161:987-1019
  4. Menter et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 1. Overview of psoriasis and guidelines of care for the treatment of psoriasis with biologics. J Am Acad Dermatol 2008;58:826-50
  5. Menter et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 3. Guidelines of care for the management and treatment of psoriasis with topical therapies. J Am Acad Dermatol 2009;60:643-59
  6. Menter et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 4. Guidelines of care for the management and treatment of psoriasis with traditional systemic agents. J Am Acad Dermatol 2009;61:451-85
  7. Menter et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 5. Guidelines of care for the treatment of psoriasis with phototherapy and photochemotherapy. J Am Acad Dermatol 2010;62:114-35
  8. Samarasekera E, Sawyer L, Parnham J, Smith CH; Guideline Development Group. Assessment and management of psoriasis: summary of NICE guidance. BMJ. 2012 Oct 24;345:e6712
  9. Special Authority forms – PHARMAC
  10. Schmitt J, Rosumeck S, Thomaschewski G, Sporbeck B, Haufe E, Nast A. Efficacy and safety of systemic treatments for moderate-to-severe psoriasis: meta-analysis of randomized controlled trials. Br J Dermatol. 2014 Feb;170(2):274-303. doi: 10.1111/bjd.12663. PubMed PMID: 24131260.

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