Three cases of linear lichen planus caused by dental metal compounds

A Review of Linear Lichen Planus Case Reports

ABSTRACT

Lichen linear planus is a rare variant of lichen planus that appears as pruritic, polygonal, purple papules in a blaschkoid distribution. This review critically assesses all reported cases of linear lichen planus (LLP) for proposed etiology, clinical and histologic traits, treatment options, and recurrence. A PubMed search from inception through March 2023, followed by article screening and full-text review, identified 51 unique cases of LLP. Data from each case including the sex of the patient, anatomic distribution of lesions, biopsy results, proposed etiology, treatment, and recurrence were recorded. LLP did not show a significant gender or age predilection, most frequently presented unilaterally with pruritus, and involved numerous anatomic regions. Various triggers including metal implants, vaccinations, infections, malignancy, and pregnancy were identified. The most common histopathologic descriptions included band-like lymphocytic or lichenoid infiltrate, basal liquefactive, vacuolar degeneration, hypergranulosis, hyperkeratosis, civatte or colloid bodies, melanin incontinence, and orthokeratosis. Treatment options, duration of treatment, and recurrence rate of LLP lesions were variable. Although LLP is rare, dermatologists should be aware of this presentation and appropriate diagnostic and treatment options because swift diagnosis can reduce patient morbidity.

Lichen Planus: What is New in Diagnosis and Treatment?

Lichen planus (LP), an idiopathic, multifaceted chronic inflammatory disease with a heterogeneous clinical presentation, affects approximately 0.5-1% of the population. The various clinical manifestations of LP fall into three broad categories, namely cutaneous, appendageal, and mucosal, with further subclassification depending on the morphology and distribution patterns of individual lesions. There is mounting evidence that LP has systemic associations, including autoimmune conditions, glucose intolerance, dyslipidemia, and cardiovascular disorders. Cutaneous hypertrophic and mucosal forms of LP are at a heightened risk for malignant transformation. Familiarity with these potential associations in conjunction with long-term follow-up and regular screening could lead to a timely diagnosis and management of concomitant conditions. In addition, the frequent quality of life (QoL) impairment in LP underscores the need for a comprehensive approach including psychological evaluation and support. Several treatment strategies have been attempted, though most of them have not been adopted in clinical practice because of suboptimal benefit-to-risk ratios or lack of evidence. More recent studies toward pathogenesis-driven treatments have identified Janus kinase inhibitors such as tofacitinib, phosphodiesterase-4 inhibitors such as apremilast, and biologics targeting the interleukin-23/interleukin-17 pathway as novel therapeutic options, resulting in a dramatic change of the treatment landscape of LP. This contemporary review focuses on the diagnosis and management of LP, and places emphasis on more recently described targeted treatment options.

Lichen Planus

Lichen planus (LP) is a T cell-mediated disease affecting the stratified squamous epithelia of the skin and/or mucus membrane. Histologically, the disease is characterized by a lichenoid inflammatory infiltrate and vacuolar degeneration of the basal layer of the epidermis. LP has three major subtypes: Cutaneous, mucosal and appendageal LP. Rarely, it may affect the nails in the absence of skin and/or mucosal changes. LP may also be induced by several drugs, typically anti-hypertensive medication or be associated with infections, particularly viral hepatitis. The diagnosis is based on the clinical presentation and characteristic histological findings. Although the disease is often self-limiting, the intractable pruritus and painful mucosal erosions result in significant morbidity. The current first-line treatment are topical and/or systemic corticosteroids. In addition, immunosuppressants may be used as corticosteroid-sparing agents. These, however are often not sufficient to control disease. Janus kinase inhibitors and biologics (anti-IL-12/23, anti-IL17) have emerged as novel future treatment options. Thus, one may expect a dramatic change of the treatment landscape of LP in the near future.

Pediatric lichen planus pigmentosus possibly triggered by mercury dental amalgams

Lichen planus pigmentosus is uncommon in childhood and its treatment is often challenging. We report a case of cutaneous lichen planus pigmentosus in a 10-year-old boy, without oral mucosal involvement, two months after an amalgam dental restoration. The diagnosis was based on the histopathological examination of a skin biopsy, the positive patch test to mercury, and the improvement after amalgam removal. Our case report suggests that metal allergy may play a role, and amalgam replacement may be followed by clinical improvement.

Hypohidrosis and metal allergy: Trigger factors for unilateral lichen planus

Unilateral lichen planus (LP) is a rare clinical variant of LP. The etiology of unilateral LP has not been clarified, although various causes have been reported because of the characteristic distribution. We focused on the contribution of metal allergy and sweating in the development of unilateral LP in this case. To confirm the presence of metal allergy, patch tests with metal allergens were performed. To investigate the cause of the unilateral distribution in unilateral LP, the function of sweating and sweat leaking in the dermis was assessed by a thermoregulatory sweat test and immunohistochemical staining of dermcidin. The patch tests with SnCl₂ , H₂ PtCl₆ , ZnCl₂ and MnCl₂ were positive. The thermoregulatory sweat test using the starch-iodine method (Minor test) with sweating provoked by heat stimulation revealed hypohidrosis of the affected area, whereas no skin lesions were observed on the dorsal hand and wrist where sweating was normal. Histopathological examination showed keratin plugging of the acrosyringium and lymphocytic infiltrations in the papillary and subpapillary dermis around the intraepidermal and intradermal eccrine duct in the affected area. The immunohistochemical staining of dermcidin confirmed sweat leakage in the subpapillary dermis in the affected area. The symptoms refractory to the topical steroids were markedly improved after removal of the dental metals. The coexistence of metal allergy and sweat leakage in the hypohidrotic area may be involved in the development of unilateral LP.

Anti-inflammatory effects of astaxanthin in the human gingival keratinocyte line NDUSD-1

Oral lichen planus is a chronic inflammatory disease that affects the mucous membrane of the oral cavity and can contribute to the development of other diseases. Inflammation in oral lichen planus is a T-cell-mediated autoimmune disease that acts through cytotoxic CD8⁺ T cells to trigger apoptosis of keratinocytes. However, the specific cause of oral lichen planus remains unknown and no effective medical treatment has yet been established. Astaxanthin is a carotenoid pigment with capacity for anti-inflammatory and anti-oxidant activities. In this study, we evaluated whether astaxanthin could be used to improve the pathology of oral lichen planus by reducing inflammation. In particular, the anti-inflammatory effects of astaxanthin on the chronic inflammation caused by lipopolysaccharide derived from Escherichia coli O55 in human gingival keratinocytes (NDUSD-1) were evaluated. Following astaxanthin treatment, localization of nuclear factor κB/p65 and the level of inflammatory cytokines (interleukin-6, tumor necrosis factor-α) tended to decrease, and cell proliferation significantly increased in vitro. These results suggest that astaxanthin could be useful for improving chronic inflammation such as that associated with oral lichen planus.

A case of linear lichen planus

Linear lichen planus (LLP) is a very rare form of lichen planus (LP) characterized by a linear distribution of the lichenoid lesions. It usually follows the lines of Blaschko with unilateral involvement. We report such a case of LLP. A 50-year-old man presented with slightly pruritic, linear, violaceous, papular lesions on the right side of his jaw. A biopsy specimen demonstrated the typical histology of LP. Based on the clinical and pathological findings, the diagnosis was LLP.

Periodontal status in patients with oral lichen planus: a study of 90 cases

OBJECTIVE

This study was carried out to relate periodontal status to the oral lesions in patients with oral lichen planus (OLP).

MATERIALS AND METHODS

Periodontal status was evaluated in 90 patients with OLP and in 52 controls, in terms of the plaque index (PII), simplified calculus index (CIS) and periodontal disease index (PDI).

RESULTS

No significant differences were observed between the two groups as regards the different periodontal indices. The plaque and calculus indices were higher in the more extensive forms of OLP (P = 0.02 and P = 0.012, respectively), and in the presence of gingival involvement (P = 0.004 and P = 0.04). A significant association was also observed between the presence of atrophic-erosive lesions and increased periodontal deterioration (P = 0.037).

CONCLUSIONS

Increased plaque and calculus deposits are associated to a significantly higher incidence of atrophic-erosive gingival lesions in patients with OLP.