Lichen planus

  • Definition

    Lichen planus is a disease in which there is an itchy rash on the skin or in the mouth.

    Causes, incidence, and risk factors

    The exact cause of lichen planus is unknown. However, it is likely to be related to an allergic or immune reaction.

    Risks include:

    • Exposure to medications, dyes, and other chemical substances (including gold, antibiotics, arsenic, iodides, chloroquine, quinacrine, quinide, phenothiazines, and diuretics)
    • Disorders such as hepatitis C

    Lichen planus generally affects middle-aged adults. It is less common in children.