Zosteriform Lichen Planus on the Trunk: A Case Report of a Rare Clinical Entity

Zosteriform lichen planus is a variant of cutaneous lichen planus that may develop at the site of healed herpes zoster or may evolve spontaneously with no previous history of herpes zoster or varicella-zoster virus infection. Lichen planus is an immune-mediated disorder that affects the skin and mucous membrane. Nonetheless, its exact etiology remains unclear. The lesion consists of polygonal, pruritic, flat-topped papules that may coalesce to form a plaque. This is a case of a 39-year-old female presenting with a three-month history of pruritic skin lesion over the right side of her trunk. On dermatological examination, there were large, discrete, band-like, hyperpigmented, papular patches following Blaschko’s lines on the right side of the trunk and abdomen. The histological examination of a biopsy taken from the lesion showed hypergranulosis, sawtooth rete ridges, band-like inflammatory infiltrate, confirming the diagnosis of lichen planus and was treated with topical steroids. Based on the findings, a planer, pruritic skin rash that follows Blaschko’s lines distribution rather than dermatomal distribution should raise the suspicion of zosteriform lichen planus.