Abstract
Lichen planus pigmentosus is an uncommon dermatological condition characterized by hyperpigmented and dark-brown macules. It is a rare variant of lichen planus, one of the most common cutaneous extrahepatic manifestations of chronic hepatitis C virus infection. The cutaneous extrahepatic manifestations may indicate an undetected chronic hepatitis C virus infection, showing the need for thorough evaluation in patients presenting with these dermatological conditions. This case report presents a case of lichen planus pigmentosus in a 60-year-old male, initially complained of an itchy dark brown macule on his right temple, which progressively enlarged, covered almost the entire face, and became thicker in several areas. Then, he was diagnosed with chronic hepatitis C virus infection and liver cirrhosis. Dermoscopy examination showed gray-brown dots, globules, and peri-eccrine gray-brown pigmented dots. Laboratory tests revealed low ferritin levels, a positive antinuclear antibody test, but a negative antinuclear antibody profile. The histopathological examination showed basal vacuolar changes on the epidermis and interface dermatitis extending to the area of the hair follicle infundibulum, with melanin pigment deposits between the fibro-collagen connective tissue accompanied by inflammatory and peri-adnexa lymphocytes, and fibrosis around the hair follicles in the dermis, supporting the diagnosis of lichen planus pigmentosus. The patient was treated with sun avoidance and photoprotection, mometasone furoate 0.1% cream twice a day, and direct-acting antiviral agents. Improvement was observed clinically and supported by spectrophotometry examination. This case highlights lichen planus pigmentosus as a potential indicator of previously undetected hepatitis C virus infection, recommending hepatitis C virus testing for patients with lichen planus pigmentosus.