Psoriasis
Psoriasis is a systemic, immune-mediated inflammatory skin disease that typically follows a chronic relapsing-remitting course. It most commonly presents with well-demarcated erythematous plaques with silver-white scale, although several subtypes exist.
This updated UKMLA guide to psoriasis is based on NICE CG153 and NICE CKS, which covers causes, triggers, symptoms, diagnosis, and management.
Epidemiology
Males and females are equally affected
Bimodal peak age of onset:
- 20-30 y/o, and
- 50-60 y/o
Most people with psoriasis have a positive family history
Pathophysiology
Skin lesions of psoriasis occur due to:
- Epidermal hyperproliferation
- Abnormal keratinocyte differentiation
- Lymphocyte inflammatory infiltration
Clinical Features
Psoriasis follows a chronic relapsing-remitting course
Triggers
Trigger factors (KISS ME):
- K – Koebner phenomenon (trauma to the skin – e.g. scratching, piercing, tattoos, burns)
- I – Infection (Streptococcal infection is strongly associated with guttate psoriasis)
- S – Stress
- S – Steroid withdrawal
- M – Medications (beta blocker, lithium, ACE inhibitors, NSAIDs, chloroquine, trazodone, terfenadine, tetracycline, penicillin)
- E – Environmental factors (smoking, alcohol)
Hormonal changes also influence disease activity
- High levels of disease activity may be seen during puberty, post-partum, and during the menopause
- Psoriasis typically improves in pregnancy
UV light exposure often improves psoriasis (which explains why phototherapy is a treatment option). In contrast, UV light can worsen other skin conditions, such as rosacea.
Presentation
Psoriasis typically presents with well-demarcated erythematous plaques +/- silver-white scaling (depending on the subtype and affected site)
Different forms of psoriasis:
| Form | Description |
|---|---|
| Plaque psoriasis (80-90% cases) | Common sites:
Classic features:
In dark skin individuals, the plaques usually have a grey colour and possible post-inflammatory hyperpigmentation |
| Flexural psoriasis (inverse psoriasis) | Common sites:
Elderly, immobile and overweight / obese patients are at increased risk Classic features:
|
| Localised pustular psoriasis (2nd most common) | Lesions are seen on the palms and soles
|
| Guttate psoriasis | Guttate psoriasis is more common in <30 y/o
Typically preceded by a Streptococcal infection (esp. URTI):
|
| Nail psoriasis |
Classic features:
Nail psoriasis is associated with an increased risk of psoriatic arthritis. Nail changes are common in psoriatic arthritis, occurring in up to 90% of affected patients. However, the presence of nail psoriasis does not automatically mean the patient has psoriatic arthritis. |
Associations
Psoriasis may be associated with other conditions:
| Associated condition | Description |
|---|---|
| Psoriatic arthritis | Psoriatic arthritis is a seronegative inflammatory arthritis affecting up to 30% of patients with psoriasis
Typical presentation:
~20% of patients with psoriatic arthritis do NOT develop skin psoriasis |
| Cardiometabolic |
|
| GI |
|
| Malignancy |
|
Complications
2 serious, potentially life-threatening forms of psoriasis can occur:
| Erythrodermic psoriasis | Characterised by diffuse, widespread, severe psoriasis that affects >90% of the body surface area
Precipitating factors include:
Key features:
|
| Generalised pustular psoriasis |
May cause fever, malaise, tachycardia, weight loss, and hypothermia. |
Long-term psychosocial complications include:
- Depression
- Anxiety
- Relationship difficulties
- -ve Body image, low self-esteem
- Feelings of shame, guilt, embarrassment
- Limitations of activities (e.g. those requiring skin exposure like swimming)
Management
Emergency / Urgent Referral Presentations
The following are dermatological emergencies:
- Erythrodermic psoriasis
- Generalised pustular psoriasis
ALL patients require immediate same-day specialist assessment and management.
Management principles of erythrodermic psoriasis: [Ref]
- Consider stopping all non-essential medications
- Apply large amounts of emollients (mainly ointments to improve skin barrier function)
- Topical corticosteroids
- Treat any underlying cause
Specialist Referral Presentations
Refer to dermatology if ANY of the following:
- Localised pustular psoriasis
- Diagnostic uncertainty
- Extensive psoriasis (>10% of body surface area)
- Moderately severe or above psoriasis, as measured by the Physician’s Global Assessment
- Psoriasis is resistant to topical therapy in primary care
- There is a significant impact on the person’s physical, psychological, or social well-being
If psoriatic arthritis is suspected → urgent referral to rheumatology
Guttate Psoriasis
Reassure that it is usually a self-limiting condition that typically resolves within 3–4 months, and reassure that it is not infectious.
Management options:
| Disease extent | Recommended management |
|---|---|
| Widespread lesions (>10% of body surface area affected) | Urgent referral to dermatology to consider phototherapy |
| Non-widespread lesions | Offer both the options of:
Topical drug treatment involves:
Very potent corticosteroid preparations should not be used in primary care. |
Do not use anti-streptococcal antibiotics (e.g. phenoxymethylpenicillin) to treat guttate psoriasis triggered by a recent upper respiratory tract infection, or recurrent episodes of guttate psoriasis
Stable Plaque Psoriasis and Non-Emergency Forms
General / Conservative Management
Patient education:
- Explain that treatment is aimed at control of symptoms rather than cure
- Complete clearance of skin lesions may not be possible
- Reassure that it is NOT an infectious condition
Give lifestyle advice to reduce the risk of exacerbations:
- Smoking cessation, if appropriate
- Advise drinking alcohol within recommended limits
- Weight loss if the patient is overweight or obese
- Assess and manage stress / anxiety / distress / depression
Pharmacological Management
General approach (step up if ineffective):
- Step 1: topical therapy in primary care
- Step 2: phototherapy in secondary care
- Step 3: systemic therapy in secondary care
There are slight variations depending on the site affected, see below for full details.
NICE recommends offering step 1 topical therapy PLUS step 2 or 3 secondary care treatment options at the same time if topical treatment alone is unlikely to adequately control psoriasis, such as:
- Extensive disease (>10% of body surface area affected)
- At least moderate on the static Physician’s Global Assessment,
- Topical treatment is ineffective (e.g. nail disease)
Step 1 (Primary Care): Topical Therapy
All patients:
- Offer regular topical emollient (to reduce scale and itch) PLUS
- Further topical therapy (depending on the affected sites, as outlined below)
Psoriasis on Trunk and Limbs
Note on topical therapy examples:
- Potent corticosteroids: betamethasone, beclometasone dipropionate, fluticasone, mometasone furoate
- Very potent corticosteroid: clobetasol propionate
- Vitamin D preparation: Calcipotriol (Dovonex®), Calcitriol, Tacalcitol
- Dovobet® is a combined topical corticosteroid and vitamin D preparation (calcipotriol with betamethasone)
| Step | Topical therapy | Description and step up |
|---|---|---|
| 1 | Potent corticosteroid PLUS vitamin D once daily for 4 weeks
The steroid and vitamin D should be administered at different times (1 in the morning and 1 in the evening) |
If there is a good response → continue topical treatment until skin is clear/nearly clear
If there is a poor response after the 4-week course:
An alternative to continuing the topical corticosteroid for another 4 weeks is to step up directly to step 2 management. |
| 2 | Stop the topical corticosteroid, and give topical vitamin D twice daily | If there is a poor response after 8-12 weeks → proceed to step 3 |
| 3 | Stop the topical vitamin D and give:
|
If there is a poor response → proceed to step 4 |
| 4 | Consider a combined topical preparation containing a potent corticosteroid and vitamin D once daily for 4 weeks | If there is a poor response → proceed to step 5 |
| 5 | Consider short-contact dithranol | Also:
|
Safety information on topical corticosteroids:
- Continuous use may cause irreversible skin atrophy and striae, unstable psoriasis, systemic side effects (when applied continuously and extensively)
- Do not use very potent corticosteroids continuously at any site for longer than 4 weeks
- Do not use potent corticosteroids continuously at any site for longer than 8 weeks
- Do not use very potent corticosteroids in children and young people
Topical vitamin D preparations should be avoided in the following situations:
- Use on the face
- Pregnancy
- Breastfeeding
Scalp Psoriasis
Note on topical therapy examples:
- Potent corticosteroids: betamethasone, beclometasone dipropionate, fluticasone, mometasone furoate
- Very potent corticosteroid: clobetasol propionate
- Vitamin D preparation: Calcipotriol (Dovonex®), Calcitriol, Tacalcitol
- Dovobet® is a combined topical corticosteroid and vitamin D preparation (calcipotriol with betamethasone)
1st line: topical potent corticosteroid once daily for 4 weeks
If no improvement after 4 weeks:
- Try a different formulation of topical potent corticosteroid, and/or
- Apply topical agents to remove adherent scale before application of the topical steroid
If still no improvement after a further 4 weeks:
- Combined topical corticosteroid and vitamin D preparation once daily for up to 4 weeks, OR
- Topical vitamin D once daily (for those who cannot use steroid and with mild to moderate scalp psoriasis)
If still no improvement:
- Very potent corticosteroid for 2 weeks, in adults only, OR
- Coal tar once or twice daily, OR
- Refer to specialist
Face / Flexural / Genital Psoriasis
1st line: topical mild / moderate potency corticosteroid once / twice daily for 2 weeks
- Mild potency: hydrocortisone
- Moderate potency: clobetasone butyrate, hydrocortisone butyrate
If ineffective or requires continuous treatment to maintain control:
- Calcineurin inhibitor twice daily for up to 4 weeks (only to be initiated by a specialist)
Be aware that the face, flexures and genitals are particularly vulnerable to steroid atrophy and that corticosteroids should only be used for short-term treatment of psoriasis (1 to 2 weeks per month)
Do NOT use potent or very potent corticosteroids on the face, flexures or genitals.
Step 2 (Secondary Care): Phototherapy
1st line: narrow-band UVB light therapy
Other options:
- Broad-band UVB light therapy
- Psoralen plus UVA (PUVA) phototherapy
Frequency and doses:
- 2-3 times a week
- Dose is based on the person’s ‘minimal erythema dose’ and sun-reactive skin type
Step 3 (Secondary Care): Systemic Therapy
1st line: conventional systemic therapy:
- 1st line: methotrexate
- 2nd line: ciclosporin, should be offered instead of methotrexate as 1st line if any of the following:
- Rapid / short-term disease control needed (e.g. psoriasis flare)
- Patient is considering conception
- Palmoplantar pustulosis
- 3rd line: acitretin
If conventional systemic therapy failed → consider targeted immunomodulatory therapy (initiated and supervised only by consultant dermatologists)
- TNF-alpha inhibitors (e.g. adalimumab, etanercept, infliximab)
- IL-12/23 inhibitor (ustekinumab)
- IL-17 inhibitor (brodalumab)
- IL-23 inhibitor (e.g. guselkumab)
Summary of Topical Corticosteroid Use in Psoriasis
Corticosteroid Potency and Examples
The potency of a topical corticosteroid preparation is determined solely by the corticosteroid molecule/component itself, regardless of the formulation or concentration used
The following examples were derived from the BNF: [Ref]
| Potency Class | Examples of Topical Corticosteroids |
|---|---|
| Mild |
|
| Moderate |
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| Potent |
|
| Very Potent |
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Summary of Topical Corticosteroid Use in Psoriasis (By Site)
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Site of psoriasis
|
1st line topical steroid potency
|
Maximum duration / recommended use schedule
|
Key restriction
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|---|---|---|---|
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Trunk and limbs
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(often used initially in combination with a topical Vitamin D preparation)
|
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Very potent preparations should not normally be used in primary care
|
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Scalp
|
|
||
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Face, flexural, and genital
|
|
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Do NOT prescribe potent/very potent TCS to these areas due to the greater risk of adverse effects like skin atrophy
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References