1Resident Physician, Department of Pediatrics, Morsani College of Medicine, University of South Florida, Tampa, FL
2Morsani College of Medicine, University of South Florida, Tampa, FL
3Associate Professor of Pediatrics, Department of Pediatrics, Morsani College of Medicine, University of South Florida, Tampa, FL
A 3-year-old boy presented to our clinic for penile lesions that first appeared 3 to 4 weeks earlier.
History. Similar lesions were not found on the scrotum or elsewhere on the body. The lesions had grown very slightly but had not caused any pain or itching while flaccid or erect. He had no known trauma to the area and was electively circumcised at age 1 for phimosis without any reported complications. The patient had a history of mild persistent asthma and resolved infantile eczema. The family denied any recent upper respiratory symptoms or fevers, and the patient had no identifiable sick exposures. The family did not note any changes to urinary or stooling patterns, dysuria, fever, abdominal discomfort, nor was there a family history of dermatologic or immunologic concerns, human papillomavirus, herpes simplex virus, or other oral cold sores.
Physical examination findings revealed scattered, fleshy pink papules convalescing on the left lateral edge of the penile shaft, not extending to glans. Scar tissue reflected circumcision without abnormalities (Figure).
Figure. Lesions isolated to the lateral dorsum of the penis.
Diagnostic testing. In our patient’s case, we diagnosed the condition based on the patient’s history and physical examination alone.
Correct answer: B. Lichen nitidus
The patient’s condition was diagnosed as penile lichen nitidus, with characteristic flesh-colored papules appearing exclusively on the lateral dorsum of the penile shaft (as shown in the Figure). The lesions were asymptomatic, and the history and physical examination were inconsistent with infectious sources of papules given a lack of ill-appearance, tenderness, spread, or fever.
Differential diagnosis. Pearly penile papules are also typically skin-colored and asymptomatic; however, these lesions typically appear as small dome-shaped papules in a ring distribution at the coronal sulcus of the glans.1 Sebaceous hyperplasia is also an incorrect diagnosis as the patient did not have the usual yellow or greasy appearance of typical sebaceous overgrowth. Lichen planus is typically systemic with raised, violaceous, flat-topped polygonal papules often presenting with associated pruritis and tenderness.1
Treatment and management. In our patient’s case, there was no need for specific treatment. The mother was reassured and advised to monitor for any progression of symptoms.
Outcome and follow-up. This patient has not developed any worsening symptoms or disease progression. Lesions appeared similar in size and pattern at the 4-year well child visit, approximately 9 months after initial visit.
Discussion. Lichen nitidus is a rare chronic inflammatory condition that most commonly presents in children and young adults without preference for race, sex, or circumcision status.2,3 Patients typically present with multiple, discrete, raised, shiny, flesh-colored papules 1 to 2 mm in diameter on the penile shaft, upper extremities, and abdomen and can cluster in relation to recent skin trauma.1,3-6
Most patients are asymptomatic, but families may seek treatment secondary to a more extensive distribution, pruritis, or abnormal cosmetic appearance. Although rare, this generalized distribution may involve the nail beds and palms. Nail thickening, ridging, pitting, or detachment may be seen in addition to nonspecific periungual inflammation or violaceous shiny papules.7 Oral involvement can occur and may result in flat, grayish mucosal papules.1,4 Both actinic and purpuric (hemorrhagic) lichen nitidus have been described in the literature as well. Actinic lichen nitidus often occurs along sun-exposed areas of the skin and appear more often as plaques whereas the hemorrhagic subtype typically presents secondary to inflammatory, degenerative changes within the capillary vessels in the dermis.8,9
Familial cases have been reported in the literature, indicating a potential genetic component. Correlations have also been drawn to Down syndrome, HIV, Crohn disease, Niemann-Pick disease, amenorrhea, and treatment with nivolumab.1,5,7
Lichen nitidus has unclear pathophysiology, although it is largely thought to have an immunologic basis. It has been hypothesized that hypersensitivity to suspected antigens prompting Langerhans cells and T-cell activation may be most relevant. The resulting lymphocyte accumulation manifests dermatologically as the flesh-colored papules.10 Other infectious agents in addition to certain medications could also theoretically activate these cell-mediated responses.2 Clinical diagnosis can be supported with direct histologic sampling, which is often not completed in most suspected cases given the typical asymptomatic course. Classically, granulomatous infiltration of lymphocytes, macrophages, Langerhan cells, and multinucleated epithelioid histiocytes are seen. These cells are surrounded by extensions of thinned, parakeratotic epidermal ridges giving a characteristic “claw clutching a ball” appearance.2,10
Lichen nitidus is self-limited and often resolves within months to a year without intervention. Postinflammatory hyperpigmented macules may replace the lesions, but these should also resolve within a few months.2,5 In persistent lichen nitidus, topical or systemic corticosteroids may be used.2,3 In patients with generalized lichen nitidus, expanded treatment options, including photochemotherapy, antihistamines, topical calcineurin inhibitors, and dinitrochlorobenzene and diphenylcyclopropene immunotherapy, have been shown to be effective.2,3,7,11,12
This case report highlights the importance of considering lichen nitidus in the differential diagnosis in cases of identified asymptomatic skin lesions without infectious contact.
Havlicek E, Doniparthi A, Kiluk V. Lichen nitidus. Consultant. 2023;63(9):e1. doi:10.25270/con.2023.09.000001.
Received January 24, 2023. Accepted May 16, 2023. Published online September 11, 2023.
The authors report no relevant financial relationships.
Elizabeth Havlicek, DO, Resident Physician, Department of Pediatrics, Morsani College of Medicine, University of South Florida, 2 Tampa General Circle, STC Suite 5034, Tampa, FL 33606 (email@example.com)