Lichen nitidus is a benign, chronic, cutaneous eruption characterized by the presence of small, discrete, uniform, often skin-colored papules that present in clusters or linear arrays. It most commonly affects children and young adults, although it can be found in patients of all ages.

Lichen nitidus may be generalized or focal, but it is commonly found on the chest, abdomen, flexor surfaces of the upper extremities, dorsal hands, and anogenital region (including the shaft and glans of the penis). Lichen nitidus actinicus is a variant of lichen nitidus that has been reported more frequently in Black individuals as well as individuals from the Middle East and Indian subcontinent. Patients may complain of pruritus over affected areas, although these micropapules are typically asymptomatic.

While the etiology of lichen nitidus remains unclear, it is important to note that it is typically not associated with laboratory abnormalities. Medication-related cases (following administration of nivolumab, tremelimumab, mogamulizumab, and interferon alpha) and familial forms have been reported.

Lichen nitidus is chronic and persistent, but the majority of patients ultimately clear spontaneously over the course of several months without residual atrophy or pigmentary changes.