(HealthDay News) -- Lichen planus is a disease that results in a rash on the skin or inside the mouth. While its exact cause isn't known, it's believed triggered by an allergic or immune system reaction.

The U.S. National Library of Medicine says common symptoms of lichen planus include:

  • Lesions on the tongue, cheek or gums.
  • Bluish white bumps in the mouth.
  • Mouth sores that may progress to painful ulcers.
  • Lesions on the skin that can itch, look scaly or shiny, and may form an ulcer or blister.
  • Dryness of the mouth.
  • Loss of hair.
  • Ridges that form in the nails.
  • A metallic taste in the mouth.