Description

• Lichen simplex chronicus (LSC) is a chronic dermatitis resulting from chronic, repeated rubbing or scratching of the skin. Skin becomes thickened with accentuated lines (“lichenification”).
• Definition/terminology (1):
  • LSC: localized lichenified plaques often with excoriations
  • Prurigo nodularis (PN): a chronic pruritic condition which is frequently more broadly distributed across multiple regions as nodules
  • Neurodermatitis: include other chronic itchy conditions, such as PN and atopic dermatitis

Epidemiology

Geriatric Considerations
Most common in middle age and elderlyPediatric Considerations
Rare in preadolescents

Etiology and Pathophysiology

• Itch–scratch cycle leads to a chronic dermatosis. Repeated scratching or rubbing causes inflammation and pruritus, which leads to continued scratching.
• Primary LSC: scratching secondary to nonorganic pruritus, habit, or a conditioned response to stress/anxiety
• Common triggers are excess dryness of skin, heat, sweat, and psychological stress.
• Secondary LSC: begins as a pruritic skin disease that evolves into neurodermatitis, which persists after resolution of the primary condition; precursor dermatoses include atopic dermatitis, contact dermatitis, lichen planus, stasis dermatitis, psoriasis, tinea, and insect bites.
• There is a possible relation between disease development and underlying neuropathy, particularly radiculopathy or nerve root compression.
• Pruritus-specific C neurons are temperature sensitive, which may explain itching that occurs in warm environments.

Risk Factors

• Anxiety disorders
• Dry skin
• Insect bites
• Pruritic dermatosis

General Prevention

Avoid common triggers such as psychological distress, environmental factors such as heat and excessive dryness, skin irritation, and the development of pruritic dermatoses.

Commonly Associated Conditions

• PN is a nodular variety of the same disease process.
• Atopic dermatitis
• Anxiety, depression, and obsessive-compulsive disorders