Psoriasis: presentation, diagnosis and management

Introduction

Psoriasis is a lifelong, immune-mediated inflammatory skin disease that is associated with comorbidities such as psoriatic arthropathy, mental health issues, cardiovascular disease and metabolic syndrome^​1​. Psoriasis affects 1.3–2.8% of the UK population^​2​. It can occur at any age, but there are two peak ages of onset: 20–30 years of age (early-onset psoriasis, also referred as type 1) and 50–60 years of age (late-onset psoriasis, also referred as type 2). Early-onset psoriasis is associated with a strong family history, whereas late-onset psoriasis is more sporadic, its genetic background is unclear and is often linked to environmental triggers^​3​. It affects men and women equally, although localised pustular psoriasis is more common in women than in men^​2​. 

Physical symptoms include itching, pain and dryness — sometimes with painful cracks or bleeding. These symptoms can affect quality of life, emotional wellbeing and social functioning. The severity of psoriasis varies, but even limited disease affecting visible or sensitive areas, such as the face, genitals or scalp, can substantially affect wellbeing^​1,4​.

Pharmacists working across primary and secondary care play an important role in the effective management of psoriasis. In the community setting, pharmacists are often the first healthcare professionals approached for advice on persistent skin symptoms or the selection of over-the-counter treatments. In general practice and the hospital setting, pharmacists can support the safe use of topical treatments, systemic and biologic therapies, including appropriate monitoring in line with clinical guidance.

This article provides a structured overview of psoriasis, outlining its clinical features, diagnosis and management, as well as the contribution of pharmacists in optimising care across the patient pathway.

Causes, risk factors and pathophysiology

The exact cause of psoriasis is unknown, but it involves a combination of genetic and external factors^​5​. Psoriasis has a major genetic component, with heritability estimated to be 60–90%^​6​. External factors that can exacerbate flare-ups include physical trauma, tobacco, excessive use of alcohol, obesity, infection, stress, weather and taking certain drugs, such as beta-blockers, lithium, non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors and antimalarials^​7​. These factors activate keratinocytes in the epidermis, initiating the inflammatory cascade.

Activated keratinocytes release pro‑inflammatory cytokines, including tumour necrosis factor-alpha (TNF‑α), interleukin-1 (IL‑1) and IL‑36, which stimulate dendritic cells within the dermis. These dendritic cells play a central role in bridging innate and adaptive immunity by secreting key cytokines, particularly IL‑12 and IL‑23^​7​.

IL‑12 promotes differentiation of naïve T cells into T‑helper 1 (Th1) cells, while IL‑23 supports the expansion and survival of T‑helper 17 (Th17) cells. Along with Th22 cells, these T‑cell subsets produce effector cytokines, such as interferon‑γ (IFN‑γ), TNF‑α, IL‑17 and IL‑22, which act directly on keratinocytes^​7​.

These cytokines drive keratinocyte hyperproliferation, abnormal differentiation and increased inflammatory mediator release, creating a self-amplifying inflammatory loop. In parallel, an imbalance between pro-inflammatory T cells and regulatory T cells impairs immune tolerance and contribute to the development of chronic disease^​7​.

The sustained immune activation results in epidermal thickening, scale formation and inflammatory infiltration, which leads to the production of the characteristic erythematous, well‑demarcated plaques seen in psoriasis (see Figure 1)^​8​.

Figure 1: Psoriasis pathogenesis and targeted therapies

Signs and symptoms 

Psoriasis usually presents as symmetrically distributed, red, scaly plaques with well-defined edges. The scale is typically silvery white. The plaques usually persist without treatment^​9​. 

The symptoms of psoriasis can include itching, burning or soreness, while the plaques could occasionally crack and bleed. Psoriasis affecting the toenail and fingernail is often associated with discolouration and pitting^​9​. These include clearly defined erythematous plaques covered with silvery scales, which are frequently located on the scalp, trunk and extensor surfaces of the limbs.

Red-flag symptoms to look out for include sudden worsening or widespread involvement — generally more than 10% of the body surface area — especially if associated with fever, malaise or systemic illness. These symptoms may indicate erythrodermic or pustular psoriasis and will require urgent specialist dermatology review. Joint pain, morning stiffness, swollen fingers or toes, or signs of infection, such as pain, oozing or crusting, should also raise concern for psoriatic arthritis or secondary infection, which prompts further assessment^​9,10​ (see Figure 2). For a summary of each type of psoriasis, see Figure 3^{​9,11,12​}.

Figure 2: Psoriasis plaques with silvery scales 

DermNet

Types of psoriasis

Figure 3: Gallery of psoriasis lesions

Diagnosis

Psoriasis is predominantly a clinical diagnosis based on patient history and the characteristic appearance and distribution of lesions. In most cases, routine laboratory investigations are not required to confirm the diagnosis. Psoriasis can be diagnosed in primary care; however, referral to dermatology is recommended if there is diagnostic uncertainty. Biopsy is only required when there is atypical presentation^​13​.

Management

There is no cure for psoriasis, but effective treatment can significantly control symptoms and improve quality of life. Management is individualised according to disease severity, affected areas, patient preference, comorbidities and response to previous therapies^​11,13​.

Tools are normally used to assess the severity of psoriasis and the impact of psoriasis. Common tools include the Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI). These measures help inform treatment decisions and monitor response^​13​.

The management of psoriasis often involved topical therapy along with systemic therapies. In severe cases, biologic therapies and targeted small-molecule agents may be indicated^​11,13​.

Topical therapy

For patients with mild psoriasis, first-line treatment consists of emollients, which restore skin barrier function, reduce dryness and scaling, as well as improve tolerability of other topical agents^​14​. Emollients should be used regularly and continued even when lesions improve.

Topical anti‑inflammatory therapies include vitamin D analogues (e.g. calcipotriol) and topical corticosteroids, either used alone or in combination. Vitamin D analogues reduce keratinocyte proliferation, while corticosteroids suppress cutaneous inflammation. Vitamin D analogues may cause local irritation and should be used cautiously in patients with disorders of calcium metabolism. Combination products can enhance efficacy and improve adherence by simplifying treatment regimens. The potency and duration of topical corticosteroids should be carefully selected to minimise adverse effects, particularly when used on sensitive areas such as the face, flexures or genitals^​14​.

Prolonged or inappropriate use of topical corticosteroids can lead to adverse effects, such as skin atrophy, telangiectasia and rebound flares, which can be minimised by limiting duration, using appropriate potency and stepping down treatment when control is achieved^​11​.

Additional topical options used in selected cases include coal tar preparations, dithranol and topical calcineurin inhibitors, particularly for facial or intertriginous psoriasis^​14​.

Phototherapy

For patients with moderate psoriasis who have not responded adequately to topical therapies, phototherapy may be considered^​14​. Narrowband ultraviolet B is the most commonly used modality and can be effective in reducing disease severity^​14​. Treatment requires specialist supervision owing to cumulative ultraviolet exposure. Adverse effects include erythema and an increased long-term risk of skin ageing and malignancy. Phototherapy is contraindicated in patients with a history of skin cancer or photosensitivity disorders, while monitoring includes regular assessment of treatment response, skin reaction and cumulative UV dose^​11​.

Systemic therapies

Patients with moderate-to-severe psoriasis, or disease significantly affecting quality of life, may require systemic treatment. Conventional systemic agents include methotrexate, ciclosporin and acitretin^​14​. These therapies act by suppressing immune‑mediated inflammation or normalising keratinocyte proliferation but are associated with potential toxicity, requiring regular laboratory monitoring and careful patient selection^​14​.

Methotrexate is administered weekly, either orally or subcutaneously. Its use is associated with adverse effects including hepatotoxicity, myelosuppression and gastrointestinal disturbance. It is also contraindicated in pregnancy and in patients with significant liver disease^​15​.

Ciclosporin is given orally and is effective for rapid disease control; however, it is associated with nephrotoxicity, hypertension and increased infection risk, as well as contraindicated in patients with uncontrolled hypertension or severe renal impairment^​16​.

Acitretin is an oral retinoid, which helps to normalise keratinocyte differentiation. It is highly teratogenic and can cause mucocutaneous dryness, hyperlipidaemia and hepatotoxicity. Acitretin is also recommended that women avoid conceiving for three years after discontinuing the medication^​17​.

Biologic and targeted therapies

In patients with severe or refractory disease, biologic therapies and targeted small‑molecule agents may be indicated^​14​. These include monoclonal antibodies targeting tumour necrosis factor (TNF), interleukin-17 or interleukin-23 pathways, as well as targeted oral small molecules such as phosphodiesterase-4-inhibitors, such as apremilast. Biologic therapies are administered subcutaneously or intravenously, while small molecules are given orally. These therapies can increase the risk of infection, including reactivation of latent tuberculosis and are contraindicated in patients with active serious infections. They require caution in those with history of malignancy or certain comorbidities, such as inflammatory bowel disease and heart failure, depending on the therapy used^​18​.

Self-care advice 

Self-care measures are an essential component of psoriasis management. Patients should use emollients frequently; avoid known triggers, such as smoking, alcohol, stress and skin trauma; and adhere closely to prescribed treatment regimen^​19​. Education on correct topical application techniques is particularly important to optimise outcomes. Taking a soothing bath in lukewarm water with added Epsom salts, oatmeal or oil can help relieve itching and remove scales; however, patients should limit bath time to 15–20 minutes, as long, hot baths can increase dryness and irritation^​19​.

Monitoring and review

Ongoing monitoring and review is essential to assess treatment response, identify adverse effects and guide escalation or de-escalation of therapy. The frequency of review depends on disease severity and the type of treatment being used.

Topical therapy

Patients managed with topical therapy should be reviewed after four weeks to assess response and adherence, because incorrect or inconsistent application is a common cause of poor outcomes^​13​. Once stable, follow-up can be reduced. Review should focus on changes in disease severity, including the extent of involvement and plaque characteristics, alongside identification of local adverse effects such as skin atrophy from corticosteroids. Treatment potency and duration should be adjusted accordingly^​13​.

Phototherapy

For patients undergoing phototherapy, monitoring is carried out each treatment session for acute skin reactions, such as erythema and tracking cumulative ultraviolet exposure, to reduce long-term risks, including skin malignancy^​11​. Treatment response is reviewed regularly to determine whether therapy should be continued or stopped. 

Systemic therapy

Patients receiving systemic therapies require baseline investigations, including full blood count, liver and renal function, and other tests depending on the therapy. Monitoring is typically more frequent during initiation (e.g. every one to two weeks), then reduced to every two to three months once stable. Review should include both clinical response and laboratory results to detect toxicity, such as hepatotoxicity with methotrexate or nephrotoxicity with ciclosporin, alongside assessment of adverse effects and ongoing treatment need^​14,15​.

Biologic and target therapy

For biologic and targeted therapies, baseline screening for infections, such as tuberculosis and viral hepatitis, is required prior to initiation. Patients are usually reviewed every three to six months in specialist care, while in some cases the monitoring can be reduced to once a year for stable patients taking biologics therapy. Monitoring is focused on treatment efficacy, infection risk and tolerability. Patients should be advised to report symptoms of infection promptly and periodic blood monitoring may be required depending on the specific agent^​18​.

All therapies

At all stages, review should also consider quality of life and comorbidities, because psoriasis is associated with increased cardiovascular risk and psychological burden^​20​. Assessment should therefore include impact on daily functioning, screening for anxiety or depression, and evaluation of cardiovascular risk factors, such as blood pressure, lipids, smoking status and weight.

Patient counselling and support

One of the most helpful things that pharmacists can do is educate patients on the disease and management options. Education should include common triggering factors, such as stress, infections, smoking, alcohol, drugs and weather changes. Identifying and addressing these triggers can help to reduce flare-ups and improve disease control.

Patients should be consistently encouraged to adhere with treatment to help improve quality of life. Psoriasis can have a psychological impact and can negatively affect self-esteem and lead to patient’s feeling isolated owing to feeling ashamed of their skin. Psoriasis symptoms can begin between the ages of 15 and 25 years, a time when teens and young adults are particularly vulnerable to body-image issues and in a social environment at school where their condition may be misinterpreted^​21​. 

Pharmacists can help tackle the stigma associated with the condition by explaining that it is not contagious. Providing reassurance and normalising the condition can support patients’ confidence and reduce the social discomfort linked to visible symptoms. 

Patient support groups play a valuable role in providing emotional support, practical advice and a sense of community. Organisations such as The Psoriasis Association UK offer educational resources, helplines and opportunities for patients to connect with others living with psoriasis.