What is the description of psoriasis?

Psoriasis Description

Psoriasis is a chronic, genetic, systemic inflammatory disease characterized by well-demarcated, erythematous plaques covered with silvery-white scales that are often pruritic or painful, affecting approximately 2% of the population. 1

Core Pathophysiology

The disease represents an immune-mediated inflammatory disorder with a strong genetic component that can be triggered by environmental factors 1. The fundamental defect involves dramatically accelerated epidermal cell turnover—approximately 4 days compared to the normal 28 days—resulting in immature cell deposition on the skin surface 2.

Clinical Presentation

Classic Features

• Morphology: Distinct, circular, well-circumscribed red papules or plaques with grey or silvery-white dry scale 3
• Distribution: Typically symmetric involvement of scalp, elbows, knees, lumbosacral area, and body folds 3
• Symptoms: Disfiguring, scaling lesions that may be painful or severely pruritic, causing significant quality of life impairment 1

Clinical Variants

The disease presents in multiple phenotypes 1, 4:

• Plaque psoriasis (most common): Classic raised, scaling plaques
• Guttate: Small (1-10mm) salmon-pink papules with fine scale, common in patients under 30 years, primarily on trunk 1
• Inverse: Erythematous plaques with minimal scale in skin folds (axillary, genital, perineal, inframammary areas) 1
• Pustular: Visible neutrophil collections appearing as pustules, either generalized (von Zumbusch variant with fever and toxicity) or localized to palms/soles 1
• Erythrodermic: Generalized erythema covering nearly entire body surface with variable scaling, potentially causing hypothermia, dehydration, fever, and malaise 1

Systemic Nature

Psoriasis is fundamentally a multisystem disease, not merely a skin condition 1. Associated comorbidities include:

• Psoriatic arthritis (seronegative spondyloarthropathy) 1
• Inflammatory bowel disease 1
• Cardiovascular disease and increased myocardial infarction risk 5
• Metabolic syndrome components (diabetes, hyperlipidemia, obesity) 5
• Depression and significant psychosocial burden 5
• Increased lymphoma risk 5

Disease Course

Psoriasis follows a chronic, relapsing-remitting pattern that waxes and wanes throughout a patient's lifetime, often modified by treatment initiation and cessation, with few spontaneous remissions 1. The visible nature of lesions ensures both physical and profound psychosocial effects 2.

Extracutaneous Manifestations

Beyond skin involvement, psoriasis can affect:

• Oral mucosa: Red patches on dorsal tongue surrounded by yellow-white borders 3
• Ocular: Various ophthalmic complications, though often clinically subtle 3
• Nails: Frequently involved, contributing to disease severity assessment 5