Contact leukomelanosis induced by the leaves of Piper betle L (Piperaceae): A clinical and histopathologic survey

Background: In April 1997, an unusual pigmentary disorder was noticed by de rmatologists in Taiwan. All patients had a history of using facial dressing s with steamed leaves of Piper betle L. (Piperaceae). Objective: Our purpose was to clarify the evolution and the origin of this unique leukomelanosis. Methods: Fifteen patients with an unusual pigmentary disorder, who visited our clinic in September and October 1997, were asked to complete a question naire designed to elicit the history related to the disorder. Eight of thes e 15 patients underwent skin biopsies: 6 on the mottled hyperpigmented area (group A) and 2 on the hypopigmented area (group B). All 8 specimens were prepared with hematoxylin-eosin, Masson-Fontana, and S-100 stains. Results: The results of the questionnaire revealed that these patients had all experienced a temporary erythematous reaction in the first few days of the use of the facial dressing, and 9 of them also complained of an accompa nying stinging sensation. A bleaching effect became noticeable approximatel y 1 week to 1 month later Eight patients reported that the hyperpigmentatio n and confetti-like hypopigmentation occurred after overexposure to the sun . In both groups, histopathologic examination revealed some melanophages in the dermis. Masson-Fontana staining of specimens from group A showed local interspersed depigmentation and hyperpigmentation in the basal epidermis a nd pigmentary incontinence in the dermis. This picture was different from t he homogeneous depigmentation within basal epidermis in specimens from grou p B. In both groups, S-100 staining was negative for melanocytes in the dep igmented area. Conclusion: The clinical course and histopathologic findings suggest that t he evolution of this pigmentary disorder can be divided into 3 stages. The first stage is the immediate bleaching stage, when an irritant reaction is usually conspicuous. The second stage consists of prominent hyperpigmentati on visible both grossly and microscopically. The final stage is characteriz ed by confetti-like depigmentation. It may be induced by chemicals in the b etel leaves such as phenol, catechol, and benzene derivatives, perhaps thro ugh inhibition of melanin synthesis or melanocytotoxicity.