Lichen nitidus

• most commonly seen in children and in young adults
• is an incidental finding in most patients
  • most commonly presents as an incidental finding on physical examination or after the patient notices an insidious onset of the lesions
  • characteristically asymptomatic
  • physical examination reveals pinpoint- to pinhead-sized skin-colored papules that may be scaly or have a central depression
    • usually are found on the forearms, trunk, and the glans and shaft of the penis.
• aetiology is unknown
• because lichen nitidus is rare, definitive establishment of the epidemiology is difficult
  • a small study of 43 cases demonstrated a male-to-female ratio of almost 4:1, although the generalized (confluent) form may be more common in women
  • no racial predisposition or known genetic inheritance pattern has been noted.
  • primarily affects children and young adults, with a median age of seven years in males and 13 years in females
• thought to be a variant of lichen planus
• can be discrete or generalized:
  • in the discrete form, papules typically do not coalesce; however, they may form or group at sites of trauma or skin pressure (the isomorphic or "Koebner” phenomenon)
  • in the generalized (confluent) form, papules coalesce into red-yellow to brown plaques, especially in joint flexures, wrist and forearm ventral surfaces, or inframammary areas, making the clinical diagnosis more challenging
  • biopsy may be helpful because lichen nitidus has a characteristic histologic appearance.
• does not itch - unlike lichen planus
• common sites include the forearms, wrists, lower abdomen and penis " occasionally lichen nitidus may coexist with true lichen planus
• spontaneous resolution can occur with no residual atrophy or pigmentary changes
• tends not to respond well to treatment and may persist for long periods

Treatment options include - topical steroids, short course of systemic corticosteroids, UV therapy (1,2)

Reference:

• 1. Update (August 18th 2005):53.
• 2. Pielop J, Hsu S. Photo quiz : Tiny, Skin-Colored Papules on the Arms and Hands. AAFP 2005; 71(2)