Top Tips: Psoriasis in Adults

Dr Catherine Fernando Explores the Latest Guidance on Psoriasis to Provide 12 Top Tips on Managing Adults with this Chronic Condition in Primary Care

Psoriasis is a chronic, immune-mediated, inflammatory disease that affects up to 3% of the UK population.^1,2 It has a similar incidence in men and women and can occur at any age, although there are two peaks of onset (20–30 years and 50–60 years).² Around 40–50% of patients with the condition have a family history of psoriasis.¹

Approximately 90% of people with the condition have chronic plaque psoriasis, which presents as symmetrical, monomorphic, hyperkeratotic, erythematous plaques with adherent silvery-white scale.^1,3–5 Lesions vary from 1 cm to several centimetres in diameter, and common sites include the scalp, extensor surfaces, and lumbosacral region.^1,5 Other types of psoriasis include guttate psoriasis, inverse (flexural) psoriasis, pustular psoriasis, and erythrodermic psoriasis.

This article provides 12 top tips for primary care practitioners managing adults aged over 18 years with psoriasis, covering assessment, advice, treatment, and referral. Readers are advised to consult individual summaries of product characteristics for further information about all treatments discussed in this article (see also the British National Formulary treatment summary on psoriasis at bnf.nice.org.uk/treatment-summaries/psoriasis).⁶

1. Use Appropriate Tools to Assess Disease Severity

To guide treatment, it is important that the severity of a patient’s psoriasis is measured.⁷ Severity of psoriasis can be determined by its coverage of a person’s body surface area (BSA) as follows:⁸

• mild psoriasis: less than 5% of BSA
• moderate psoriasis: 5–10% of BSA
• severe psoriasis: more than 10% of BSA.

A patient’s palm is equivalent to around 0.5% of their BSA, and may be used to estimate the extent of disease.⁸ Other validated tools for assessing the severity of psoriasis include the Psoriasis Area and Severity Index⁹ and the six-point Physician/Patient Global Assessments, in which the patient or clinician rates their perception of severity on a scale from zero to five (clear, nearly clear, mild, moderate, severe, or very severe).^7,8 The patient's perceived impact of their disease may not correlate with objective measures of disease extent or severity.⁷

2. Consider Differential Diagnoses

The list of differential diagnoses for psoriasis is long and should be considered in all patients, particularly those who are unresponsive to first-line therapy.^1,10 See Box 1 for a list of key differential diagnoses^10–12—it is worth noting that many of these conditions can coexist with psoriasis.  

3. Be Aware of Atypical Presentations, and Enquire Specifically About Genital Psoriasis

Genital Psoriasis

Patients are often too embarrassed to mention genital psoriasis, or may worry that it is a manifestation of a sexually transmitted infection. However, a clinician asking directly about the presence of genital involvement allows the patient to express their concerns and seek treatment.¹³

Psoriasis of the vulva usually presents as smooth, nonscaly, erythematous areas, and scratching of an area may cause dryness, infection, and lichenification.¹³ Psoriasis of the penis often presents as multiple small, red patches on the glans or shaft, with skin that can be either scaly or smooth and shiny.¹³

Flexural and Facial Psoriasis

Flexural and facial psoriasis can also present atypically, leading to diagnostic confusion. Flexural psoriasis generally affects the axillae, inframammary folds, perineum, umbilicus, or gluteal cleft, but—because of friction and humidity in these sites—there may be no scale.^5,13 Lesions tend to be symmetrical, shiny, red, and well demarcated, and can be extremely irritant, particularly when sweating.¹³

Facial psoriasis can also present as well-demarcated plaques, but is often almost indistinguishable from seborrhoeic dermatitis.¹⁴ Indeed, both conditions may coexist (known as sebopsoriasis).¹⁴

4. Assess for Comorbidities and Psoriatic Arthritis

People with psoriasis are at increased risk of cardiovascular disease, cerebrovascular disease, venous thromboembolism, hyperlipidaemia, metabolic syndrome, hypertension, type 1 or type 2 diabetes, autoimmune disease (such as inflammatory bowel disease or coeliac disease), renal failure, and nonalcoholic fatty liver disease.^1,8,15–17 Patients with a young age of onset, severe disease, or psoriatic arthritis are most at risk.^1,15,18

It is therefore important to assess people with any type of psoriasis for the presence of comorbidities, particularly for modifiable cardiovascular risk factors such as blood pressure, lipid levels, blood glucose, and body mass index.^3,7 Lifestyle interventions and advice should be offered when relevant to help patients with smoking cessation, weight reduction, and limiting alcohol intake.^3,7

Psoriatic Arthritis

Up to 30% of patients with psoriasis develop psoriatic arthritis.^1,16 Annual screening for psoriatic arthritis, which can be done using the Psoriasis Epidemiology Screening Tool,¹⁹ can help to identify this destructive, debilitating disease early, with any suspicion of arthritis prompting urgent referral to Rheumatology for assessment.^1,3,7

Psoriasis Reviews

Box 2 contains a list of areas to assess in any review of psoriasis in primary care.^{1,3,7,8,16,19–21} Such reviews would ideally be undertaken annually. 

5. Don’t Underestimate the Impact of Psoriasis on Psychosocial Health

Psoriasis is a stigmatising disease that is associated with significant psychological and social morbidity and, as such, people with psoriasis are at increased risk of anxiety, depression, and alcohol abuse.^8,22,23 Psoriasis can therefore lead to relationship difficulties, social anxiety, and unemployment.^22,23

Clinicians should assess the psychological impact of psoriasis on their patients and manage associated distress, anxiety, or depression appropriately.^3,7 It is important to ask patients about how psoriasis affects their home life, work, and/or education, asking whether they feel depressed, anxious, or lonely, as well as whether their psoriasis affects relationships with partners, family, friends, or carers.^3,7,23 The Dermatology Life Quality Index can be used for more formal assessment.^3,20,21

6. Offer HIV Testing in Patients with Severe Psoriasis

A new case of psoriasis may be the first sign that a patient has HIV. Furthermore, for patients with known psoriasis, the presence of HIV can cause a flare up or make their psoriasis less responsive to treatment.²⁴ Therefore, as severe psoriasis is an HIV indicator condition, the British Association for Sexual Health and HIV and NICE recommend offering HIV testing to patients with severe, recalcitrant, or atypical psoriasis to aid early identification and treatment of HIV.^1,25,26 

7. Ensure that Patients Know the Triggers of Psoriasis

Psoriasis can be triggered or exacerbated by a number of lifestyle and environmental factors (see Box 3^1,8,27,28). Awareness of these can empower patients to modify their behaviour to reduce flares.

Patients will likely also benefit from being provided with general information about psoriasis. See Box 4 for further resources that may be useful in this regard.

8. Prescribe Copious Quantities of Emollients

Emollients are essential in the treatment of psoriasis, but are often underprescribed and underutilised.²⁹ They help to soften scale, increase absorption of active products, relieve pruritis, and maintain remission.^1,29 All patients should be encouraged to use an emollient at least daily—even as often as four times daily when necessary.²⁹

If scale is very thick, it may be necessary to use additional descaling agents prior to active treatment.¹ The Primary Care Dermatology Society (PCDS) recommends either 5% salicylic acid in yellow soft paraffin, to be applied to thick plaques twice daily, or Diprosalic^® ointment (salicylic acid, betamethasone dipropionate), which will also soften scale.¹

9. Harness the Benefits of Combination Products to Increase Compliance

When initiating treatment for psoriasis, NICE recommends individual active components (a steroid and either vitamin D or a vitamin D analogue) applied separately, morning and evening.³ However, many clinicians instead offer combination products (containing calcipotriol and betamethasone) as first-line treatment in primary care.¹ Indeed, the PCDS recommends this, suggesting that more rapid improvement tends to increase patient compliance and thus achieve more rapid control.¹ Options of combination products include Enstilar^® foam (betamethasone dipropionate, calcipotriol monohydrate), Wynzora cream^® (calcipotriol, betamethasone dipropionate), Dovobet gel^® (betamethasone dipropionate, calcipotriol monohydrate), and Dovobet ointment^® (betamethasone dipropionate, calcipotriol monohydrate).¹

The preparation of choice should initially be applied for 4 weeks.³ Patients who improve within 4–6 weeks should then attempt to maintain clearance with regular use of emollients and as-needed use of topical treatments,³ with some patients benefiting from twice-weekly Enstilar^®, for example, as maintenance therapy.¹ However, if there is little improvement after 6–8 weeks, alternative treatments should be considered.³

Tar preparations (such as Exorex^® lotion [coal tar solution]) may be useful for large, thin plaques, particularly on areas of thin skin such as the shins, or for very large numbers of small plaques.¹ Dithranol preparations are also very effective for solitary plaques, but can be messy and cause pigmentation of the skin.¹

10. Treat Psoriasis Differently Based on Disease Area

Examples of appropriate treatments by area include:^1,3,13,14

• 1% hydrocortisone for the face
• Eumovate^® cream (clobetasone butyrate) around the hairline of the scalp, on genitals, and in flexures
• Trimovate^® cream (clobetasone butyrate, nystatin, oxytetracycline calcium) for genitals and flexures (if coexisting yeast infection is suspected)
• vitamin D compounds, such as Curatoderm^® lotion/ointment (tacalcitol monohydrate) or Silkis^® ointment (calcitriol), which may be used on genitals and flexures, especially if a clinician is concerned about overuse of topical steroids
• calcineurin inhibitors, such as Elidel^® cream (pimecrolimus) or Protopic^® ointment (tacrolimus monohydrate), which may be an effective alternative to steroids, and can be prescribed by clinicians with specialist knowledge; however, their use in psoriasis is unlicensed.

Psoriasis of the Scalp

For chronic plaque psoriasis of the scalp, treatments can be very messy, and temporary hair loss can occur with the removal of scale.³⁰ Treatment options include:³⁰

• treating thick scale by:
  • applying a topical treatment such as Sebco^® (coal tar, sulphur, salicylic acid in a coconut oil base) to the scalp, covering it with a plastic shower cap, and leaving it for 1 hour
  • washing this out with a shampoo, such as Capasal^® (salicylic acid, coconut oil, coal tar, distilled)
  • applying a topical treatment, such as Dovobet^® gel, once daily to the scalp
• using long-term maintenance shampoos, such as Polytar^® (coal tar solution) shampoo—a 5-minute tar-based treatment for mild scale—or Dermax^® shampoo (benzalkonium chloride) for patients who do not like the smell of tar
• using topical applications to treat flare ups, such as Dovobet^® gel, Betacap^® (betamethasone valerate; applied to the scalp and washed out at the other end of the day), or Etrivex^® shampoo (clobetasol propionate; washed out after 15 minutes).

Nail Psoriasis

Approximately 50% of patients with psoriasis have nail involvement, with signs including pitting, onycholysis, subungual hyperkeratosis, and oil drop or salmon patch.^5,31 To manage nail psoriasis, clinicians can:^31,32

• remind patients to keep their nails short, and inform them that nail varnish can disguise nail changes and will not cause harm
• consider prescribing a potent topical steroid, potentially alongside a vitamin D analogue, to be applied once daily for 3 months after the nail is cut back as far as possible
• refer patients with severe nail disease causing functional impairment to secondary care.

11. Recognise that Unmonitored Use of Potent Steroids Can Lead to Life-Threatening Medical Emergencies

Topical steroids are a mainstay of treatment, especially for flexural, genital, and facial psoriasis, but care must be taken to avoid potent or prolonged use of corticosteroids as they may cause irreversible skin atrophy, striae, and systemic side effects.^1,3,13,14 Unregulated use of potent steroids may even precipitate life-threatening emergencies, such as erythrodermic psoriasis or generalised pustular psoriasis.^3,33,34

12. Refer Patients to Secondary Care as Appropriate

NICE recommends referring patients with psoriasis to secondary care under the circumstances outlined in Box 5.³

Secondary care treatments for psoriasis include:^1,3

• phototherapy—narrow-band ultraviolet (UV) B or psoralen and UV A (PUVA) treatment may be offered, but a patient’s lifetime dose is limited because of the associated risk of skin cancer
• ciclosporin—an immunosuppressive agent with associated risks of hypertension and renal failure, which is best used in younger adult patients who have not already received light therapy
• methotrexate—effective in skin disease and psoriatic arthropathy, but not safe in pregnancy; patients must be monitored for liver impairment and aplastic anaemia
• acitretin—a systemic retinoid that is highly teratogenic and needs to be avoided 3 years prior to pregnancy
• hydroxyurea, fumaric acid esters (Skilarence® [dimethyl fumarate]), and apremilast.

Biologics and biosimilars can also be used—under specialist supervision—for both psoriasis and psoriatic arthritis, and are recommended in patients who have been unresponsive or intolerant to second-line treatments.^1,3

Summary

Primary care plays an essential role in the management of psoriasis. With effective assessment, self-management advice, and prescribing, primary care practitioners can greatly improve the lives of patients and help them to live with this stigmatising disease.