Dermoscopic Features of Acute Widespread Lichen Planus

Lichen planus is a chronic inflammatory condition characterized by the appearance of polygonal, discrete, and violaceous papules. It can affect the skin, mucous membranes, and nails, often presenting with symptoms such as itching and discomfort. While the clinical diagnosis of lichen planus is often straightforward, dermoscopy has emerged as a valuable tool in enhancing diagnostic accuracy, particularly in atypical or widespread cases. This article explores the dermoscopic features of acute widespread lichen planus, as illustrated in two case reports, and discusses the clinical and histopathological findings that support the diagnosis.

Case Reports

Patient 1

The first patient was a 63-year-old woman who presented with a 3-month history of an itchy rash on her limbs and trunk. The onset of her symptoms followed a severe cold, during which she took acetaminophen (Tylenol) for relief. After recovering from the cold, she noticed a mildly pruritic papular eruption on her abdomen and sacrococcygeal region. Over time, the rash spread to her arms and legs. Physical examination revealed multiple violaceous round papules and plaques distributed over her abdomen, sacrococcygeal region, arms, and legs. Wickham striae, a classic feature of lichen planus, were barely visible on the lesions. Notably, there were no oral lesions, and hepatitis serology was negative.

Dermoscopic examination of the lesions on the sacrococcygeal region was performed using a desktop dermoscopy device (CH-DSISI-2000, Guangzhou Chuanghong Medical Technology Co., Ltd, China). The dermoscopic findings revealed annular crystalline white striae accompanied by prominent linear vessels at the periphery, arranged in a characteristic radial distribution. These features were consistent with the dermoscopic patterns observed in lichen planus. A skin biopsy was performed to confirm the diagnosis. Histopathological examination showed wedge-shaped hypergranulosis, acanthosis, liquefaction degeneration of basal cells, and a band-like lymphohistiocytic infiltration in the dermis.

The patient was treated with topical halometasone cream and tacrolimus ointment, applied daily to the lesions. She declined oral corticosteroid therapy. Over the course of two weeks, her condition improved significantly, and she continued to show further recovery with ongoing topical treatment during follow-up.

Patient 2

The second patient was a 38-year-old man with a 1-month history of an itchy rash on his limbs and trunk. His symptoms began after an upper respiratory tract infection, which resolved without medication. Shortly after recovering, he noticed reddish-brown plaques on his palms, which gradually progressed to involve his limbs and trunk. Some of the lesions were slightly scaly. Physical examination revealed violaceous polygonal flat-topped papules and plaques, measuring 1 to 2 cm in size, distributed on his limbs and trunk. His palms exhibited brown plaques with peripheral hyperpigmentation. Additionally, a reticular white pattern was observed on his oral mucosa. Hepatitis and syphilis serology were negative.

Dermoscopic examination of the lesions showed an annular and arboriform whitish line interspersed with linear and dotted vessels. These dermoscopic features are indicative of lichen planus and provided further support for the clinical diagnosis. A skin biopsy was performed, and histopathological examination revealed wedge-shaped hypergranulosis, acanthosis, basal-layer liquefaction degeneration, and lymphocytic infiltration at the epidermal-dermal junction.

The patient was treated with an intramuscular injection of compound betamethasone (1 mL) and topical halometasone cream and tacrolimus ointment, applied daily to the lesions. After two weeks of treatment, his condition improved, and he remained under follow-up care.

Discussion

Clinical Presentation of Lichen Planus

Lichen planus is a well-recognized inflammatory disorder that typically presents with violaceous, polygonal, flat-topped papules. These lesions are often accompanied by Wickham striae, which are fine, white, reticulated lines visible on the surface of the papules. While the condition commonly affects the skin, it can also involve the mucous membranes, nails, and scalp. The exact etiology of lichen planus remains unclear, but it is believed to involve an immune-mediated response triggered by various factors, including infections, medications, and stress.

In the cases described, both patients presented with widespread cutaneous involvement, which is characteristic of acute widespread lichen planus. The lesions were distributed across multiple body regions, including the limbs, trunk, and, in one case, the palms and oral mucosa. The presence of violaceous papules and plaques, along with the associated symptoms of pruritus, aligns with the typical clinical presentation of lichen planus.

Dermoscopic Features of Lichen Planus

Dermoscopy has become an invaluable tool in dermatology, allowing for the visualization of skin structures that are not visible to the naked eye. In lichen planus, dermoscopy can reveal specific patterns that aid in diagnosis, particularly in cases where clinical features are ambiguous or atypical.

In the first patient, dermoscopy revealed annular crystalline white striae accompanied by prominent linear vessels at the periphery, arranged in a radial distribution. These findings are consistent with the dermoscopic features described in lichen planus, where white striae represent areas of hyperkeratosis and acanthosis, and the linear vessels reflect the underlying inflammatory process.

In the second patient, dermoscopy showed an annular and arboriform whitish line interspersed with linear and dotted vessels. The arboriform pattern, characterized by branching white lines, is another hallmark of lichen planus. The presence of dotted and linear vessels further supports the diagnosis, as these vascular patterns are commonly observed in inflammatory skin conditions.

Histopathological Findings

Histopathological examination is the gold standard for confirming the diagnosis of lichen planus. The characteristic findings include wedge-shaped hypergranulosis, acanthosis, liquefaction degeneration of basal cells, and a band-like lymphohistiocytic infiltration in the dermis. These features were observed in both patients, providing definitive evidence of lichen planus.

Wedge-shaped hypergranulosis refers to the thickening of the granular layer of the epidermis, which is most pronounced at the tips of the rete ridges. Acanthosis, or thickening of the epidermis, is another common finding. Liquefaction degeneration of basal cells is a hallmark of lichen planus, resulting from the immune-mediated destruction of keratinocytes at the basal layer. The band-like lymphohistiocytic infiltration in the dermis reflects the inflammatory nature of the condition.

Treatment and Management

The management of lichen planus typically involves a combination of topical and systemic therapies aimed at reducing inflammation and alleviating symptoms. In both cases, topical corticosteroids (halometasone cream) and calcineurin inhibitors (tacrolimus ointment) were used as first-line treatments. These agents are effective in reducing inflammation and promoting the resolution of lesions.

The first patient declined oral corticosteroid therapy, which is often used in more severe or widespread cases. However, her condition improved significantly with topical treatment alone. The second patient received an intramuscular injection of compound betamethasone, a systemic corticosteroid, in addition to topical therapy. This approach led to a marked improvement in his symptoms within two weeks.

Conclusion

The cases presented highlight the clinical, dermoscopic, and histopathological features of acute widespread lichen planus. Dermoscopy, in particular, has proven to be a valuable diagnostic tool, revealing characteristic patterns such as annular crystalline white striae and arboriform whitish lines interspersed with linear and dotted vessels. These findings, combined with the classic histopathological features, provide a comprehensive approach to the diagnosis and management of lichen planus. Early recognition and appropriate treatment are essential in achieving favorable outcomes and improving the quality of life for patients with this condition.

doi.org/10.1097/CM9.0000000000000388

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