Lichen Planus Pigmentosus: A Clinico-etiological Study

INTRODUCTION: Lichen planus pigmentosus (LPP) is a distinct clinical entity commonly encountered in the Indian population. AIM: To study the clinicoetiological profile of LPP at a tertiary care hospital. METHODS: A total of 100 patients with clinically and histopathologically confirmed diagnosis of LPP were included. Demographic details including the age of onset, duration of disease, symptoms, and family history were obtained. History regarding any precipitating factors, cosmetics, drug intake, and associated cutaneous or systemic diseases was taken. Clinical examination of the skin, oral cavity, hair, and nails was carried out. RESULTS: Of the total 100 patients, 56 (56%) were females and 44 (44%) males with age ranging from 18 to 54 years (mean age - 31.23 years). The duration of disease ranged from 2 to 60 months with a mean of 19.31 months. Cosmetic disfigurement (68%) was the commonest complaint, followed by itching (41%) while, 30% of the patients were asymptomatic. History of topical mustard oil and hair dye application was present in 62% and 48% of the cases each. Other topicals included perfumes (24%), aftershave lotion (36%), and cosmetics (20%). Face (54%) and neck (48%) were the commonest sites affected, followed by upper back (36%), upper limbs, and chest (each 32%). A total of 11 patients showed only flexural involvement. The commonest pattern of pigmentation was diffuse (56%) followed by reticular in 16%. The color of the pigmentation varied from slate grey to brownish-black in varying proportions. A positive association was found between hypothyroidism with diffuse LPP where the P value was <0.001. CONCLUSION: LPP is a distinct clinical entity caused by diverse etiological factors and shows varied clinical patterns. All the patients should be advised to stop using mustard oil/henna/hair dye/after shave lotions and cosmetics. Hypothyroidism can be considered to be a disease associated with LPP and all the patients should be investigated for the same.