Blaschko-linear lichen planus: Clinicopathological and genetic analysis

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.

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.