A case of unilateral blaschkoid lichen planus pigmentosus

Dear Editor, Lichen planus pigmentosus (LPP) is a rare variant of lichen planus. A few cases of LPP involving linear, blaschkoid, and zosteriform patterns have been reported in the literature.2-4 We herein describe a case involving a 48-year-old female patient with unilateral abdominal involvement of LPP following the lines of Blaschko. A 48-year-old female patient was admitted to our clinic with a 2-year history of a pruritic rash localized to the right half of the abdomen. The patient’s medical history revealed that she had been using levetiracetam and levothyroxine for 8 years to treat epilepsy and hypothyroidism. On dermatologic examination, livid-brown, S-shaped, and linear-patterned macules and papules were observed from the right half of her abdomen to the right lumbar area with a tendency to coalescence (Figure 1). Mucous membranes, scalp, and nails were not affected. The results of routine laboratory tests were all within normal limits. Histopathological examination of a punch biopsy specimen from the lesions revealed hyperkeratosis, epithelial atrophy, hydropic degeneration in the basal layer, civatte bodies, band-like lymphocytic infiltrates, and pigment incontinence in the papillary dermis (Figure 2). A diagnosis of unilateral blaschkoid LPP was made based on the clinical and histopathological evaluations.