Definition of "psoriasis" [pso•ri•a•sis]

• A noncontagious inflammatory skin disease characterized by recurring reddish patches covered with silvery scales. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "For decades after Willan's description, some authors favored using the term psoriasis, while others chose the term lepra."
• "In his books, Gibert (1797-1866) used the term psoriasis, recognized secondary syphilis as a contagious entity, and established pityriasis rosea as a clinical syndrome."
• "Although he used the term psoriasis, his description is now believed to most likely represent seborrheic dermatitis."