Psoriasis Disease Background

Introduction 

Psoriasis vulgaris is a systemic, chronic, inflammatory disorder that can be transmitted genetically and is provoked by environmental factors. It primarily affects the skin and joints. It is associated with other inflammatory disorders and autoimmune diseases (eg psoriatic arthritis, inflammatory bowel disease, coronary artery disease) and is characterized by recurrent exacerbations and remissions.

Epidemiology 

Psoriasis is found in approximately 2% of the population. Its prevalence ranged from 0.5-11% in adults and 0-1.4% in children.  

In the United States, the prevalence is from 51-79/100,000 cases. In Canada, the prevalence differs by age ranging from 44-225/10,000 cases.  

According to the 2019 Global Burden of Disease (GBD) report, the prevalence of psoriasis was approximately 129/100,000 cases in Southeast Asia. The prevalence in China was consistently below 1% as reported by the Chinese Medical Association from a survey in 2008 and the GBD in 2019. Several studies in India reported that the prevalence in the country was around 0.4-2.8% affecting men more than women. A Korean-based study that utilized the Korean National Health Insurance Database from 2011-2015 mentioned that the prevalence of psoriasis was 450/100,000 cases. In Malaysia, a study claimed that the prevalence was 2-6%.  

Epidemiology-MY

Pathophysiology 

Psoriasis is a complex immune-mediated inflammatory disease involving T lymphocytes, dendritic cells, and cytokines (eg interleukin [IL]-23, IL-17, and tumor necrosis factor [TNF]) causing hyperproliferation and abnormal differentiation of the epidermis, infiltration of inflammatory cells, and vascular dilatation in genetically susceptible patients.