Clinical Challenge: White Papular Rash on 4-Year-Old Child

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A 4-year-old Hispanic boy is brought in for evaluation of a rash affecting his mid and lower back. The eruption was first noted by his parents several weeks ago and the child complains of occasional itch. No family history of eczema or other skin disorders is noted. Examination reveals multiple firm, 1- to 2-mm discrete whitish papules. No lesions are noted elsewhere.

Lichen nitidus is a rare benign inflammatory condition first described by Pinkus in 1907. The etiology and pathogenesis of lichen nitidus are still unknown.1 It typically presents as 1- to 2-mm, flesh-colored, shiny dome-shaped papules predominately on the flexor surfaces of...

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Lichen nitidus is a rare benign inflammatory condition first described by Pinkus in 1907. The etiology and pathogenesis of lichen nitidus are still unknown.1 It typically presents as 1- to 2-mm, flesh-colored, shiny dome-shaped papules predominately on the flexor surfaces of the upper extremities, chest, abdomen and genitalia in children and young adults.2 It does not exhibit predilection for any race or gender.3

Lesions can appear along lines of trauma similar to lichen planus and psoriasis in a pattern known as the Koebner phenomenon.1 Pruritus is variable and the condition is often of cosmetic concern.4 Clinical variants include linear, confluent, vesicular, hemorrhagic, spinous follicular, perforating, generalized, palmar, and plantar.5

The diagnosis of lichen nitidus is usually based on clinical presentation. The differential diagnosis includes lichen planus, keratosis pilaris, and follicular eczema. A sharply circumscribed inflammatory infiltrate within the dermis, resembling a claw clutching a ball, is a characteristic histopathologic finding. Earlier lesions are predominately lymphocytic, while later lesions may contain granulomatous inflammation with occasional giant cells.2

While some reports have suggested lichen nitidus to be a variant of lichen planus, the cutaneous and histopathologic differences between the 2 conditions are distinct. Lichen planus has an infiltrate composed of mostly helper T cells as well as orthokeratotic papules in distinction to the hyperkeratotic papules of lichen nitidus.2 Dermoscopy can be useful when diagnosing lichen nitidus and reveals white, well-circumscribed circular areas with brown shadows.6

Lichen nitidus usually resolves within several months to a year following onset. Topical or systemic corticosteroids may hasten resolution.

Alexandra Stroia, BS, is a medical student at the Lake Erie College of Osteopathic Medicine. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Cho EB, Kim HY, Park EJ, Kwon IH, Kim KH, Kim KJ. Three cases of lichen nitidus associated with various cutaneous diseasesAnn Dermatol. 2014;26(4):505-509. doi:10.5021/ad.2014.26.4.505

2. Synakiewicz J, Polańska A, Bowszyc-Dmochowska M, et al. Generalized lichen nitidus: a case report and review of the literature. Postepy Dermatol Alergol. 2016;33(6):488-490. doi:10.5114/ada.2016.63890

3. Payette MJ, Weston G, Humphrey S, Yu J, Holland KE. Lichen planus and other lichenoid dermatoses: kids are not just little peopleClin Dermatol. 2015;33(6):631-643. doi:10.1016/j.clindermatol.2015.09.006

4. Chu J, Lam JM. Lichen nitidusCMAJ. 2014;186(18):E688. doi:10.1503/cmaj.140434

5. Agharbi FZ. Lichen nitidusPan Afr Med J. 2019;32:39. doi:10.11604/pamj.2019.32.39.13564

6. Malakar S, Save S, Mehta P. Brown shadow in lichen nitidus: a dermoscopic marker! Indian Dermatol Online J. 2018;9(6):479-480. doi:10.4103/idoj.IDOJ_338_17