Blaschkoid lichen planus: Throwing a "curve" in the nomenclature of linear lichen planus

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.

A Unilateral, Pruritic Papular Eruption Following Primigravida Pregnancy

Linear lichen planus (LLP), also known as blaschkolinear or blaschkoid lichen planus, is a rare subtype of lichen planus that presents along the lines of Blaschko. While LLP has been associated with vaccinations, neoplasms, medications, and successive pregnancies, we present a case of LLP following a primary pregnancy. A 29-year-old G1P1 female presented to dermatology for the evaluation of an intensely pruritic, whorled rash confined to her left lower leg that appeared shortly after the birth of her first child. A biopsy of the lesion and subsequent histopathology confirmed the diagnosis of LLP. The patient was treated with topical steroids with minimal response to therapy and declined further treatment.

Unilateral lichen planus with Blaschko line distribution: A case report

BACKGROUND

Lichen planus (LP) with distribution of lesions along Blaschko’s lines is a rare entity, accounting for 0.24%-0.62% of all patients. Unilateral distribution of lesions in arm, leg, trunk, and waist is even less common. Approximately 10% of patients with LP manifest nail lesions.

CASE SUMMARY

A 20-year-old woman presented to our department with polygonal, purpuric, flat-topped papules over the right arm, right leg, and right side of trunk and waist for the last 5 mo. The patient initially developed nail deformation in the left middle finger with no obvious cause, followed by development of blue-purple and red maculopapular rash with pruritus. During the disease course, the skin lesions aggravated and spread to several segments due to scratching. The lesions showed unilateral distribution along the Blaschko’s lines. The diagnosis of LP along Blaschko’s lines was established based on dermoscopy and skin biopsy. Her cutaneous lesions considerably improved after 4-wk treatment with intramuscular glucocorticoid, oral acitretin, topical glucocorticoid, and retinoids.

CONCLUSION

Cases of LP involving multiple segments of the body along the Blaschko’s lines with nail damage are rare.

Blaschko-Linear Lichen Planus Pigmentosus: An Unusual Presentation

Lichen planus pigmentosus (LPP), an uncommon variant of lichen planus (LP), is characterized by diffuse hyperpigmented dark brown macules in sun-exposed areas. We report an unusual case of LPP with a blaschkoid distribution in an area of radiotherapy for breast cancer. This description is rarely reported. Its pathogeny is poorly understood and suggests an embryological origin by genetic mosaicism and also discusses the immunomodulatory role of radiotherapy in the disease.