JMIR Publications

ABSTRACT

Lichen planus pigmentosus (LPP) is a condition characterized by persistent and asymptomatic brownish-black to blue or purple-gray pigmentation, predominantly in the face and sun-exposed areas, commonly in dark-skinned individuals. The cause of LPP is unknown but postulated to be secondary to type IV hypersensitivity reaction or T-lymphocyte-mediated cytotoxic activity against basal keratinocytes. Several clinical variants of LPP have been reported. The diffuse and symmetric classical type, linear unilateral hyperpigmentation in the extremities (Blaschkoid) and segmental patterns on the trunk have been documented. Reticular, blotchy, perifollicular, annular, and gyrate patterns are also encountered. We present a 19‑year‑old male who presented with a 7-year history of asymptomatic grayish macules, patches with fine scales on the face, trunk and upper extremities and grayish plaques with thick, “ichthyosiform” scales on the lower extremities. Diagnosis of LPP was proven by histopathological finding on both the macular and ichthyosiform plaques. CD68 stain highlights the same density of pigment-laden macrophages in both the gray macule and the ichthyosiform plaque. In conclusion, the terminology “ichthyosiform lichen planus pigmentosus”is hereby proposed to be added to the clinical variants of LPP