Pigmentogenic lichen planus: Epidemioclinical profile and pathological associations

Pigmentogenic lichen planus (PPL) is a rare variant of cutaneous lichen planus characterized by hyperpigmented lesions on the tegument. This dermatosis has rarely been described in association with other diseases. The aim of our study is to describe the epidemiological profile and pathological associations of PPL in a prospective study conducted in our dermatology department in the university hospital of Marrakech, over a period of 11 months, focusing on histologically confirmed cases of PPL. We identified 65 histologically confirmed cases of PPL, with phototypes ranging from 3 to 5. The sex ratio was M/F = 0.3. The mean age was 43.5 years, with a mean duration of progression of 5 years. 32 patients had phototyped IV, 21 patients had phototyped V and 12 patients had phototyped III. There were two similar cases in the family. Triggering factors, in descending order, were stress followed by scrubbing in the Moorish bath, then sun exposure without photoprotection, drugs such as estrogens and progestogens, insulin and metformin, then the application of oils such as lavender oil, orange oil and olive oil, pregnancy, then finally the use of henna-based preparations, and coffee masks. Pruritus was present in 38 patients, then 23 patients reported aesthetic discomfort and 4 reported a burning sensation. Pathological associations were dominated by frontal fibrosing alopecia, depression, type 2 diabetes, viral hepatitis B, lichen planus pilaris, hypothyroidism and Crohn's disease.