Nodular Lichen (Lichen Ruber Planus): Causes

Pathogenesis (disease development)

The etiology (causes) and pathogenesis of lichen ruber planus are not fully understood.

Much evidence suggests that it is an autoimmune disease. It is thought to be an autoimmune reaction against keratinocytes (horn-forming cells). Destruction of basal keratinocytes by cytotoxic T cells occurs.

Etiology (Causes)

• Genetic burden – familial lichen ruber planus is rare (approximately 100 cases are known); there is a relationship to certain HLA types

The following trigger factors (possible triggers) are suspected:

• Mechanical trigger factors (scratching, rubbing, etc.).
  • Occurrence of Köbner’s phenomenon: In Köbner’s phenomenon, a non-specific skin irritation (e.g., scratching) triggers the skin symptoms that already exist due to a skin disease in another part of the body.
• Viral infections (viral infections) – prevalence (disease frequency) of HCV/HBV infections (hepatitis C/B) is 13.5 times higher in lichen ruber planus than in a comparison collective without lichen ruber planus.
• Contact allergens
• Diabetes mellitus – every second patient with lichen ruber planus shows a disorder of glucose metabolism; every fourth patient has manifest diabetes mellitus, i.e. is affected by diabetes mellitus