Clinico-dermatoscopic and Histopathological Evaluation of a Case of Generalized Lichen Nitidus

Abstract

Lichen nitidus (LN) is a rare asymptomatic skin disease composed of numerous tiny, shiny, flat papules mainly over the chest, forehead, neck, forearm, and glans penis. They are of two types based on distribution, localized which is more common compared to generalized. Dermoscopy helps in differentiating LN from other similar dermatoses such as lichen planus, keratosis pilaris, follicular eczema, lichen spinulosus, which is non-invasive. We describe a 15-year-old female with generalized lichen nitidus with palms, soles, and nail involvement with dermoscopic features and histopathological correlation.

Lichen nitidus (LN), a rare skin disease of unknown etiology and generalized LN, is even rarer. It is more common in children and young adults. There are very few cases reported with the role of dermoscopy in LN, which differentiates it from other similar dermatoses such as lichen planus, keratosis pilaris, follicular eczema, and lichen spinulosus, which is noninvasive. Here we present a case of a 15-year-old girl with minimally itchy tiny raised lesions all over the body of 6-month duration. On examination, there were multiple skin-colored flat and shiny, pinhead-sized papules mainly affecting the neck, face, upper extremities, lower extremities, trunk, palms, and soles [Figure 123]. Oral cavity was normal; fingernails showed longitudinal ridging and pits. Dermoscopy (Dinolite, USA) was performed, which on the nonpolarized mode showed loss of skin markings at site of lesion [Figure 4B] and on the polarized mode it showed multiple and white well-circumscribed circular areas with an indistinct brown shadow reflecting from white areas [Figure 5A] and linear vessels [Figure 4A]. Dermoscopy of the palmoplantar lesions revealed well-defined depressions surrounded by ring-shaped, silvery-white parallel scales [Figure 5B]. Dermoscopy of nails showed longitudinal ridges [Figure 6A]. Baseline investigations were normal. A biopsy from the papule on the back and right sole showed lymphocytes, few epithelioid cells, and plasma cells in the papillary dermis. Overlying epidermis was flattened and showed downward extension of rete ridges at the lateral margins of the infiltrate, giving a characteristic “claw clutching a ball” picture [Figure 6B]. The patient was given antihistamines and moisturizer and is under follow-up and planned for narrowband ultraviolet B (NB-UVB).

Figure 1: (A) Clinical photo showing multiple skin-colored flat and shiny, pinhead-sized papules over the forehead. (B) Similar lesions perioral area

Figure 2: (A) Multiple skin-colored flat and shiny, pinhead-sized papules over neck. (B) Similar papules over the back

Figure 3: (A) Lesions over palms. (B) Clinical photo showing longitudinal ridges and pitting over the nail

Figure 4: (A) Dermoscopy of lichen nitidus showing linear vessels. (B) Loss of skin markings at the site of lesion on nonpolarizing mode

Figure 5: (A) Well-circumscribed white areas with an indistinct brown shadow reflecting from white areas. (B) Dermoscopy of the palmoplantar lesion showing well-defined depressions surrounded by ring-shaped, silvery-white parallel scales

Figure 6: (A) Dermoscopy of nail showing ragged cuticle and longitudinal ridges. (B) Histopathology HandE showing characteristic “claw clutching a ball” picture in lichen nitidus

LN is a rare localized lichenoid dermatosis that was first described by Pinkus in 1907 of unknown etiology[¹] characterized by the presence of multiple tiny, flat, shiny papules mainly over the neck, forehead, forearms, abdomen, and penis. The generalized form of LN is still rarer with unpredictable clinical course.[²³] Dermoscopy plays a vital role in the diagnosis of LN, which on nonpolarizing mode shows loss of skin markings and on polarizing mode shows multiple, white well-circumscribed areas with an indistinct brown shadow reflecting from white areas.[⁴] Dermoscopy of palms and soles shows linear scales in parallel, discontinued by oval, well-defined depressions surrounded by ring-shaped silvery white scales. Nail involvement shows longitudinal ridges, pits, and ragged cuticle on dermoscopy. Histopathologically, white areas correspond to epidermal acanthosis and brown shadow corresponds to the foci of lymphocytes and epithelioid cells in the dermal papilla.[⁵] LN is asymptomatic and self-resolving; hence, treatment is not necessary in most cases. Indications for treatment are persistent, generalized, pruritic, and cosmetic purpose. Treatment includes topical and systemic corticosteroids, psoralen and UVA (PUVA), ultraviolet A/ultraviolet B (UVA/UVB) with corticosteroids, diphencyclopropenone, selective H1 antagonist, itraconazole, isoniazid, acitretin, and NB-UVB. In conclusion, dermoscopy is a noninvasive tool for a dermatologist, which provides vital clues in diagnosing various entities faster and can avoid the need for biopsy.

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Conflicts of interest

There are no conflicts of interest.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.