NCLEX Review Guide: Psoriasis

Disease Process

• Psoriasis is a chronic autoimmune inflammatory disorder characterized by accelerated keratinocyte proliferation and incomplete cornification, resulting in epidermal hyperplasia with a normal mitotic rate but shortened cell cycle time (3-4 days versus normal 28 days).
• The pathogenesis involves dysregulated immune response with T-cell activation and release of inflammatory cytokines (particularly TNF-alpha, IL-17, and IL-23) that stimulate keratinocyte hyperproliferation.

Triggering Factors

• Multiple factors can trigger or exacerbate psoriasis, including physical trauma (Koebner phenomenon), infections (particularly streptococcal), stress, medications (beta-blockers, lithium, antimalarials), and environmental factors.
• Systemic conditions like obesity, metabolic syndrome, and cardiovascular disease are commonly associated with psoriasis, suggesting shared inflammatory pathways that increase overall health risks.

Cutaneous Findings

• The hallmark lesions of psoriasis are well-demarcated, erythematous plaques with silvery-white scale, typically distributed symmetrically on extensor surfaces (knees, elbows), scalp, lumbosacral region, and intergluteal cleft.
• When scales are removed, pinpoint bleeding (Auspitz sign) may be observed, which is a characteristic diagnostic feature resulting from trauma to the dilated capillaries that lie close to the epidermal surface.

Clinical Variants

• Plaque psoriasis (psoriasis vulgaris): Most common form (80-90% of cases), characterized by well-defined plaques with silvery scale.
• Guttate psoriasis: Small, drop-shaped lesions often triggered by streptococcal infections, commonly affecting children and young adults.
• Pustular psoriasis: Characterized by sterile pustules that may be localized or generalized, with the generalized form being a dermatologic emergency.
• Erythrodermic psoriasis: Widespread erythema covering >90% of body surface area, potentially life-threatening due to impaired thermoregulation and risk of secondary infection.
• Inverse psoriasis: Affects intertriginous areas with smooth, red, non-scaly plaques.

Extracutaneous Manifestations

• Psoriatic arthritis affects approximately 30% of patients with psoriasis, presenting as an asymmetric oligoarthritis, spondylitis, or distal interphalangeal joint involvement, and may precede cutaneous manifestations in up to 15% of cases.
• Nail changes occur in 50% of patients with psoriasis and in 80% of those with psoriatic arthritis, manifesting as pitting, onycholysis, oil spots, and subungual hyperkeratosis.

Diagnostic Approach

• Diagnosis is primarily clinical, based on characteristic morphology and distribution of skin lesions, with skin biopsy reserved for atypical presentations or to rule out other conditions.
• Histopathological findings include acanthosis (epidermal thickening), parakeratosis (retention of nuclei in the stratum corneum), elongated rete ridges, thinning of the suprapapillary plate, and neutrophilic microabscesses (Munro's microabscesses).

Differential Diagnosis

• Conditions that may mimic psoriasis include eczema, seborrheic dermatitis, tinea corporis, pityriasis rosea, and cutaneous T-cell lymphoma, necessitating careful clinical evaluation and sometimes histopathological confirmation.
• Distinguishing features of psoriasis include well-demarcated plaques, silvery scale, predilection for extensor surfaces, and Auspitz sign, while eczema typically presents with poorly defined borders, serous exudate, and intense pruritus.

Topical Therapy

• Corticosteroids: First-line therapy for mild to moderate psoriasis, available in various potencies, with higher potency preferred for thick plaques and lower potency for facial, intertriginous, or genital involvement.
• Vitamin D analogs (calcipotriene, calcitriol): Regulate keratinocyte proliferation and differentiation, often used in combination with topical corticosteroids to enhance efficacy and reduce steroid-related adverse effects.
• Calcineurin inhibitors (tacrolimus, pimecrolimus): Useful for facial and intertriginous areas where steroid use is limited due to atrophy risk.
• Other topical agents include tazarotene (retinoid), anthralin, and coal tar, which may be used as adjunctive therapy or in rotation strategies.

Phototherapy

• Narrowband UVB (NB-UVB) is the preferred phototherapy modality for widespread psoriasis, acting by inducing apoptosis of activated T-cells and decreasing inflammatory cytokines, typically administered 2-3 times weekly until clearance.
• PUVA (psoralen plus UVA) combines oral or topical psoralen (photosensitizing agent) with UVA exposure, offering high efficacy but with increased risk of skin cancer with long-term use, thereby limiting its use in modern practice.

Systemic Therapy

• Traditional systemic agents:
  • Methotrexate: Inhibits dihydrofolate reductase, reducing DNA synthesis and inflammatory cell proliferation; requires monitoring for hepatotoxicity, bone marrow suppression, and pulmonary toxicity.
  • Cyclosporine: Calcineurin inhibitor that suppresses T-cell activation; effective but limited by nephrotoxicity and hypertension.
  • Acitretin: Oral retinoid that normalizes keratinocyte differentiation; teratogenic and requires strict contraception in women of childbearing potential.
• Biologic agents:
  • TNF-α inhibitors (adalimumab, etanercept, infliximab): Block tumor necrosis factor, a key inflammatory cytokine in psoriasis pathogenesis.
  • IL-17 inhibitors (secukinumab, ixekizumab, brodalumab): Target interleukin-17, which drives keratinocyte proliferation and inflammation.
  • IL-23 inhibitors (guselkumab, risankizumab, tildrakizumab): Block interleukin-23, which is crucial for Th17 cell development.
  • IL-12/23 inhibitor (ustekinumab): Targets the p40 subunit shared by IL-12 and IL-23.

Newer Oral Agents

• Apremilast: Phosphodiesterase-4 inhibitor that reduces production of inflammatory mediators; has a favorable safety profile without requiring laboratory monitoring, though less effective than biologics.
• JAK inhibitors (deucravacitinib): Target Janus kinase signaling pathways involved in inflammatory cytokine production; emerging treatments with efficacy comparable to some biologics.

Treatment Selection

1. Assess disease severity (mild, moderate, severe) based on body surface area affected, location, impact on quality of life, and response to previous treatments.
2. For mild disease (BSA <3%), begin with topical therapies (corticosteroids, vitamin D analogs).
3. For moderate disease (BSA 3-10%), consider combination topicals, phototherapy, or targeted systemic therapy.
4. For severe disease (BSA >10%), systemic therapy with traditional agents or biologics is indicated.
5. Consider comorbidities: presence of psoriatic arthritis favors TNF inhibitors, IL-17 inhibitors, or IL-23 inhibitors.
6. Evaluate for contraindications to specific therapies (e.g., pregnancy, liver disease, history of malignancy).
7. Monitor response to therapy and adjust as needed, with treatment goals of at least 75% improvement in disease severity.

Assessment

• Perform a comprehensive skin assessment, documenting distribution, morphology, and extent of lesions, using standardized tools like the Psoriasis Area and Severity Index (PASI) when appropriate.
• Assess for extracutaneous manifestations, including joint pain, stiffness, or swelling suggestive of psoriatic arthritis, and nail changes such as pitting, onycholysis, or subungual hyperkeratosis.
• Evaluate psychosocial impact, as psoriasis significantly affects quality of life, body image, and psychological well-being, potentially leading to depression, anxiety, and social isolation.

Nursing Interventions

• Patient education: Provide comprehensive information about psoriasis as a chronic condition, treatment options, medication administration, and importance of adherence to maximize treatment efficacy.
• Skin care: Teach proper skin care techniques, including gentle cleansing, liberal use of emollients, avoidance of harsh soaps, and proper application of topical medications.
• Trigger management: Help patients identify and avoid individual triggers such as stress, alcohol, smoking, and certain medications that may exacerbate their condition.
• Monitoring therapy: For patients on systemic therapy, ensure appropriate laboratory monitoring, recognize potential adverse effects, and facilitate timely follow-up.

Psychosocial Support

• Provide emotional support and encourage open discussion about the psychological impact of psoriasis, including feelings about body image, relationships, and social activities.
• Connect patients with support resources, including psoriasis support groups, counseling services, and organizations like the National Psoriasis Foundation for additional education and community support.

Patient Education

• Educate about the chronic nature of psoriasis, emphasizing that while treatments can control symptoms, there is currently no cure, setting realistic expectations for disease management.
• Provide information about comorbidity risks, including cardiovascular disease, metabolic syndrome, and inflammatory bowel disease, encouraging appropriate screening and healthy lifestyle modifications.
• Teach self-management strategies, including stress reduction techniques, healthy diet, regular exercise, smoking cessation, and limited alcohol consumption to help control disease activity.

Psoriasis vs. Other Skin Conditions

Psoriasis Treatment Classes

Clinical Variants of Psoriasis

Key Diagnostic Features

Treatment Selection

Monitoring Requirements

Common Pitfalls