Psoriasis



Psoriasis


Lauren Fried

Gabriela A. Cobos

David Cohen



BACKGROUND

Psoriasis is a chronic immune-mediated inflammatory disorder characterized by hyperproliferation of keratinocytes leading to epidermal hyperplasia, scaling, and inflammation. The prevalence of psoriasis is 2% to 4% in Western countries. The disease can occur at any point in life, although an increase in prevalence is seen with age. Most common peaks of onset occur between ages 30 to 39 years or 50 to 69 years.1


PRESENTATION

Patients typically present in their third or sixth decade of life with usually asymptomatic or intermittently pruritic red, scaling patches on areas pertaining to the subtypes described later.




PATHOGENESIS

The etiology of psoriasis is complex and involves an interplay between genetics, the immune system, and environment.5 Triggering events may include stress, infection, trauma, or certain medications. Once triggered, the disease process of psoriasis involves dysregulation and inappropriate activation of the cutaneous immune system. Increased activation of T cells and production of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-12, IL-17, IL-22, and IL-23, leads to hyperproliferation of keratinocytes, further T-cell activation, and vasodilation in the surrounding tissue.6,7 Accelerated cellular turnover prevents normal cellular maturation and lipid release, impairing cell-cell adhesion in the stratum corneum and leading to scaling. It is now well recognized that this inflammation is not limited to the skin and may also have profound systemic effects.


Risk Factors

Genetics are known to play a role in the development of psoriasis, with 40% of affected adults reported to have at least 1 first-degree relative with the condition.8 A number of loci have been linked to psoriasis (PSORS I-IX), with the HLA-Cw6 allele (PSORS-I) recognized as the major susceptibility gene for psoriasis.9 Psoriasis can also be triggered by environmental factors such as stress, infections (particularly bacterial), skin trauma, or certain drugs. For example, beta blockers, lithium, nonsteroidal anti-inflammatory drugs, angiotensin converting enzyme inhibitors, oral corticosteroids, and antimalarials have been reported to induce flares of or exacerbate existing psoriasis.10


Comorbidities

Psoriatic arthritis develops in up to 30% of patients with psoriasis.11 The skin precedes the joints in 85% to 90% of patients. The presence of psoriasis is an independent risk factor for a number of conditions including Crohn disease, congestive heart failure, metabolic syndrome, nonalcoholic fatty liver disease, and malignancy.12 Patients with severe psoriasis are at an increased risk of cardiovascular disease (myocardial infarction, pulmonary emboli, peripheral arterial disease, cerebrovascular accidents) and an associated approximate 6-year reduction in life expectancy.13

The associated increase in morbidity and mortality highlights the importance of a comprehensive history and physical and the need for an interdisciplinary approach in the evaluation and treatment of patients with psoriasis.


Quality of Life

In addition to dysesthetic symptoms and comorbid conditions, the perceptible nature of psoriasis can
have a dramatic impact on interactions with others, self-perception, and quality of life. Visible lesions lead to feelings of contagion, uncleanliness, and unattractiveness, impacting a patient’s perception of their acceptability to self and to others. This is reflected in commonly reported feelings of frustration, helplessness, embarrassment, and self-consciousness.14 The psychological burden of psoriasis has been reported to match those of significant chronic conditions such as congestive heart failure, myocardial infarction, and cancer.15 Furthermore, patients with psoriasis experience elevated rates of anxiety, depression, and suicidal ideation. Patients are less likely to be employed and more likely to miss days of work, with the vast majority citing psoriasis as the cause.16 It is important to consider that the impact of psoriasis on quality of life may not be correlated with clinical severity of disease. The psychosocial burden of psoriasis is substantial and should play a major role in guiding therapy. In addition, the symptomatic aspect of psoriasis is often underappreciated, with many patients experiencing pruritus or pain. This can lead to disruption of sleep and ability to participate in activities of routine daily living.

Jun 29, 2020 | Posted by in Dermatology | Comments Off on Psoriasis
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