Psoriasis

Psoriasis is a common chronic inflammatory disease of the skin that may affect up to 100 million people worldwide with an average age of onset between 20-35 years. In the US and Europe, around 2-3% of the population is estimated to be affected by psoriasis. Seventy-five percent of all cases occur for the first time before the age of 40 years. As an immune-mediated disease, psoriasis usually requires long-term treatment for control. The annual cost of psoriasis to society is an estimated US$3 billion dollars in the U.S. alone.

The majority of cases are mild or mild to moderate and are managed with topical therapy. However, 25-50% of cases are considered to have moderate to severe disease, requiring more intense, often systemic, therapy. It is believed that there are about 1.5 to 3 million US patients and 2 to 4 million European patients with moderate to severe disease. In addition, about 15-30% of the patients have associated arthritis. There is an increasing understanding of psoriasis as a systemic disease, rather than merely affecting the skin; thus, emphasizing the need of systemic therapy.