This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Lichen planus pigmentosus (LPP) is a rare form of lichen planus. It is characterized by oval or irregularly-shaped brown to gray-brown macules and patches on the skin. Areas that are exposed to sun such as the forehead, temples and neck are most commonly affected. However, the macules and patches may also develop on the trunk or in places where two areas of skin touch or rub together (i.e. the armpit, groin, etc). LPP is a chronic, relapsing condition with periods of worsening symptoms separated by periods of remission (decreasing or disappearing symptoms). The cause of LPP is unknown, but studies suggest it may be triggered by UV light, viral infections, or agents applied to the skin such as mustard oil and amla oil. Treatment for LPP depends on the symptoms in each person.
For more information, visit GARD.