Written by Thomas Hambridge

Psoriasis (also known as PsO) is a chronic, immune-mediated inflammatory disease which primarily affects the skin and joints and is characterized by scaly, erythematous plaques which are often pruritic. It is a common skin disorder with genetic underpinnings, affecting approximately 2% of the population and may also be influenced by environmental factors. In most cases, psoriasis also affects a patient’s quality of life, is often accompanied by depression and may also be associated with other inflammatory disorders such as inflammatory bowel disease, and coronary artery disease and a seronegative form of arthritis known as psoriatic arthritis. There are various treatment options available to psoriasis patients, ranging from topical steroidal based therapies, phototherapy and biological therapies which target specific immune components.

Clinical Features



Cellular Characteristics




Additional Resources


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Psoriasis in USA:

25 million people

People affected with psoriasis
in North America and Europe


The average age of
onset for psoriasis

Genes identified to be
associated with psoriasis