Psoriasis Vulgaris
A chronic autoimmune skin disease causing red, scaly plaques on extensor surfaces, driven by overactive T-cells and rapid skin cell turnover.
Emergency Management: Erythrodermic psoriasis or generalized pustular psoriasis (von Zumbusch) requires emergency hospitalization for fluid resuscitation, temperature regulation, and rapid systemic immunosuppression (e.g., Cyclosporine 3-5 mg/kg/day).
Psoriasis vulgaris is a chronic, immune-mediated inflammatory dermatosis characterized by well-demarcated, erythematous, hyperkeratotic plaques with silvery scales. It primarily affects the extensor surfaces, scalp, and lumbosacral region. The core pathology is marked by keratinocyte hyperproliferation and abnormal differentiation driven by the IL-23/Th17 axis.
Detailed Overview
Plaque psoriasis is the most common variant of psoriasis, accounting for 80-90% of cases. It is a systemic inflammatory condition that not only affects the skin but is heavily associated with cardiometabolic comorbidities such as metabolic syndrome, cardiovascular disease, and psoriatic arthritis. The dysregulation of the adaptive immune system, particularly involving dendritic cells, T-cells, and the cytokines IL-17 and TNF-alpha, maintains the inflammatory loop. Untreated, it significantly reduces quality of life, increasing risks of depression and disabling joint destruction.
Epidemiology & Demographics
Prevalence is approximately 2-3% of the global population, with higher rates in Scandinavian and Northern European populations. Bimodal age of onset: first peak at 15-20 years and second peak at 55-60 years. Men and women are affected equally.
Etiological Mechanism
A complex interaction between polygenic predisposition (specifically the PSORS1 locus, HLA-Cw6 allele) and environmental triggers such as streptococcal pharyngitis, stress, local trauma (Koebner phenomenon), and certain medications (beta-blockers, lithium).
Primary Causes
Primary cause is an autoimmune dysregulation linked to genetic susceptibility. Secondary triggers include infections (Group A Streptococcus), medications (lithium, beta-blockers, antimalarials, NSAIDs), cold/dry weather, emotional stress, and alcohol consumption.
Stressed keratinocytes release LL-37 (cathelicidin), which complexes with self-DNA/RNA to activate plasmacytoid dendritic cells via Toll-like receptors (TLR7/9). These secrete IFN-alpha, activating myeloid dendritic cells, which migrate to lymph nodes and secrete IL-12 and IL-23. This drives the differentiation of Th1 and Th17 cells. Th17 cells migrate to the skin and release IL-17A, IL-17F, and IL-22, which stimulate keratinocyte hyperproliferation (acanthosis), incomplete maturation (parakeratosis), and production of chemokines (CXCL1, CXCL8) that recruit neutrophils to form Munro microabscesses.
Diagnostic Criteria & Guidelines
Diagnosis is primarily clinical based on typical plaque morphology, distribution, and signs (Auspitz, Koebner). Skin biopsy is rarely needed but shows regular epidermal hyperplasia (psoriasiform), parakeratosis, loss of granular layer, and Munro microabscesses. Severity is measured using the Psoriasis Area and Severity Index (PASI).
For mild-to-moderate disease: Topical Betamethasone dipropionate 0.05% ointment applied BID for 2-4 weeks, often combined with a Vitamin D analog (Calcipotriene 0.005% ointment applied BID). For severe disease (>10% BSA): Systemic biologics such as Adalimumab (40 mg SC every 2 weeks after initial loading dose) or Secukinumab (300 mg SC at weeks 0, 1, 2, 3, 4, then monthly).
Second-Line & Adjunctive Therapy
Narrowband UVB (NB-UVB) phototherapy 3 times weekly. Oral therapies include Methotrexate 7.5 to 15 mg PO once weekly (with daily folic acid 1 mg), or Apremilast 30 mg PO BID (titrated over 5 days).
Surgical & Procedural Management
None primarily indicated for psoriasis. Joint replacement may be necessary for severe end-stage psoriatic arthritis.
Patient Counseling & Advice
Inform patients that psoriasis is a chronic, relapsing condition without a cure, but it is highly manageable. Emphasize that it is not contagious. Discuss the increased risk for cardiovascular disease and the importance of routine blood pressure and cholesterol screening.
Follow-Up & Monitoring Schedule
Routine PASI scoring every 3-6 months. For patients on Methotrexate, monitor CBC, LFTs, and creatinine every 1-3 months. Annual lipid panel and HbA1c screening for metabolic comorbidities.
Preventive Strategies
Avoid known triggers such as beta-blockers and NSAIDs where possible. Promptly treat streptococcal infections to prevent guttate flares. Maintain a healthy BMI.
Lifelong condition with fluctuating severity. Biologics can achieve PASI 90 or PASI 100 (complete clearance) in 60-80% of patients. Unmanaged severe disease reduces lifespan by 3-5 years due to cardiovascular events.