Abstract

Wild parsnip (Pastinaca savita) is an invasive Apiaceae species prevalent in prairies, fields, farmlands, and along roads and paths. Cutaneous contact with the sap of the plant, along with exposure of the impacted skin to ultraviolet light, leads to a chemical reaction that causes cellular damage in the epidermis. Acutely, the cellular damage manifests as tender and pruritic contact erythema with variable edema and bullae formation. This reaction is known as phytophotodermatitis. As the initial inflammatory response resolves, there is residual hyperpigmentation due to the melanocytic response to the parsnip sap that fades over the ensuing months. Although the acute and subacute stages of the cutaneous response to parsnip exposure are well documented, there is scant literature about the chronic effects. In this case report, we discuss long-term follow up of parsnip dermatitis, document the residual hyperpigmentation persisting over 4 years, and review treatment options.