Lichen Planus Pigmentosus

Lichen planus pigmentosus (LPP) is an uncommon variant of lichen planus, predominantly affecting individuals with darker skin tones, characterized by asymptomatic, dark brown to grayish macules and patches that are mainly distributed on sun-exposed areas such as the face and neck, as well as on flexural skin areas including the axillae and inguinal regions. Dermatoscopic examination of LPP reveals distinctive features depending on the location of the lesions. When it comes to facial lesions, dermatoscopy typically shows pigmented dots arranged around follicular and eccrine ostia, known as the “periostial arrangement.” These dots can be brown or gray, but only the brown dots are significantly associated with LPP. Focal brown structureless areas with sparing of ostial openings are also observed. On the other hand, extra-facial LPP mainly shows brown dots over a brown background. Additional findings may include gray dots as well as a mixture of brown and gray dots.