Occupational dermatitis to cashew nut

A 45-year-old male presented with complaints of asymptomatic brownish-black discoloration over his left hand for a 4-year duration. He was a farmer by occupation and gave the history of coming into contact with raw cashew nuts and shell oil that he used to sell by hand. Cutaneous examination revealed well-demarcated brown macules over his fingers [Figure 1a]. The rest of the cutaneous examination was noncontributory. He also shared with us an image showing a similar picture in the hands of one of his coworkers [Figure 1b]. Based on the occupational history and examination, a diagnosis of cashew nut dermatitis was made, and the patient was counseled regarding the same.

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Figure 1:

(a and b) Well-demarcated brownish macules over palms suggestive of cashew nut dermatitis.

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The cashew tree, Anacardium occidentale, belongs to the Anacardiaceae family of plants. The cashew nut is composed of an inner kernel and a double-layered outer shell. Between the layers of the shell is a highly caustic brown oily liquid. This cashew nut shell liquid contains anacardic acid and cardanol, which corrode the skin, leading to irritation and chemical burns. It also contains urushiol, which can lead to allergic/irritant contact dermatitis. Urushiol is also found in mangoes, pistachios, and poison ivy and may result in cross-sensitivity.^[1] The use of barrier creams and other personal protective measures will help prevent the same in cashew nut workers. It is important for dermatologists to be aware of the various occupational-related dermatoses and to manage them accordingly for the betterment of the affected individuals.