Cashew nut dermatitis

The urushiol dermatitis caused by plants of the Anacardiaceae family is the most common cause of acute allergic contact dermatitis. We have reported a case of cashew nut urushiol dermatitis due to ingestion of homemade cashew nut butter contaminated by cashew nut shell oil. With the precautions taken today to avoid contamination of food products with cashew urushiols, it is rare to find a case of cashew nut dermatitis in the United States. We have found no other report of contact dermatitis due to cashew nut butter. Moreover, though hinted at in the literature, there has been no previous detailed report of perianal contact dermatitis due to cashew ingestion. The fact that our patient was ill enough to require treatment with 3 weeks of systemic steroid therapy highlights the potential public health hazard of consumption of improperly prepared cashew products. However, the risk of cashew nut dermatitis today remains small, and this should not discourage cashew lovers from enjoying their treats. A final lesson to be learned from this case is that perianal eruptions may be due to materials deliberately applied to the anogenital region or to ingested antigens that remain sufficiently intact within the feces to affect perianal skin.