Occupational (betel-nut induced) pseudomelanonychia and contact dermatitis in a paan (betel-quid) vendor

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We report a 46-year-old male who presented with longitudinal brown–black nail pigmentation, oozing discharge and periungual itching. The patient was a “paan” (betel quid) vendor for the past 10 years, preparing the same and selling in his small shop. Clinical examination revealed features suggestive of paronychia, scaling and acute dermatitis over the distal phalanges. The pigmentation mimicked melanonychia, raising concern. The habitual use of ‘Paan’ – a preparation made from betel leaf, areca nut (betel nut), lime and often tobacco – is deeply rooted in Indian culture, particularly among semi-urban and rural populations. While its oral health impacts are well documented, less attention has been given to the occupational hazards faced by Paan preparers. Areca nut is a well-known irritant and allergen capable of inducing contact dermatitis.^[1] We report a case in which chronic exposure led not only to occupational contact dermatitis but also to nail dyschromia mimicking melanonychia, raising diagnostic and clinical management challenges.

A 46-year-old male presented with complaints of dark brown to black nail pigmentation involving multiple fingernails. It was accompanied by a watery discharge and persistent itching around the nails. His occupation involved preparing Paan in a roadside shop for over 10 years, involving direct and prolonged contact with betel nut and associated ingredients. Upon examination, the patient exhibited longitudinal, dark brown, dyschromic lines along the nail plate, resembling melanonychia [Figure 1]. In addition, there were periungual scaling, subacute contact dermatitis-like changes over the distal phalanges and signs of paronychia [Figure 2]. No other mucocutaneous lesions were observed. Nail scrapings were screened for fungal infection by preparing 10% KOH mount and were found to be negative. He was started on a regimen of oral Levocetirizine for relief from itching and topical clobetasol propionate (0.05%) and fusidic acid (2%) combination cream, to be applied twice daily, addressing both the inflammatory and infectious components. Nail discolouration was managed by filing the affected nails regularly. The patient was counselled about protective measures, including the use of emollients multiple times during the day and wearing polyethylene gloves during Paan preparation. In case the patient found it cumbersome to wear gloves at his work, he was advised to apply coconut oil multiple times during his workday, which could act as a barrier to the absorption of active substances from betel nut, while also being non-contaminating to his Paan preparation.

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Figure 1:

Clinical photograph of the right hand showing longitudinal dark brown-black nail dyschromia, periungual scaling and signs of paronychia over multiple fingers. The background changed to dark green for contrast. The appearance mimics melanonychia but is attributed to chronic occupational exposure to betel nut.

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Figure 2:

Clinical photograph of both hands showing pseudo-melanonychia and paronychia-like eczematous changes.

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The case highlights an under-recognised occupational dermatosis in India. Betel nut, a key component of Paan, has documented allergenic potential and can lead to both irritant and eczematous contact dermatitis. So far, a variety of chemicals have been identified from betel nut, including alkaloids, tannins, flavonoids, steroids, triterpenoids and fatty acids.^[2] The alkaloids in betel nut are the primary bioactive ingredients in research, and arecoline (methyl 1-methyl-3,6-dihydro-2H-pyridine-5-carboxylate) is considered the most significant toxic alkaloid in betel nut. Arecoline can induce a variety of disruptive changes in the DNA chain, chromosomes, and sister chromatids, and can affect DNA repair, causing oxidative stress. Its metabolites, mainly arecaidine and arecoline-N-oxide, are also genetically toxic.^[3] The bioactive substances in the Areca plant are known contact allergens in workers involved in farming and the extraction of areca nut.^[4] Several reports have implicated the role of betel nut in the pathogenesis of oral submucosal fibrosis and oral cancers. Few reports^[5] have linked contact leucoderma with betel nut chewing. The patient’s exposure was chronic and repetitive, explaining the development of both dermatitis and nail dyschromia, which mimicked melanonychia and was therefore labeled pseudo-melanonychia.

What makes this case noteworthy is the development of nail pigmentation mimicking melanonychia–a finding that often raises concern for subungual melanoma or lichen planus. However, in this context, the pigmentation resulted from chronic staining and eczematous insult, rather than melanin deposition. Such presentations can lead to diagnostic confusion, especially in primary care or dermatology outpatient departments (OPDs), where occupational history may be underappreciated during busy OPD hours, Therefore, thorough history taking is critical. Preventive strategies, including barrier protection and timely topical therapy, can greatly improve prognosis.

To conclude, this case highlights the dermatological hazards of chronic occupational exposure to Paan ingredients, particularly betel nut. Nail pigmentation resembling melanonychia in such patients should prompt clinicians to consider occupational contact dermatitis as a differential. Timely intervention with corticosteroids, antibiotics and protective measures can prevent chronicity and complications.