Botanical Briefs: Phytophotodermatitis Caused by Giant Hogweed (Heracleum mantegazzianum).

Giant hogweed (Heracleum mantegazzianum) is an invasive flowering weed that can reach a height of 13 feet. Although it is the appearance of the plant that can draw attention, contact with the sap in combination with exposure to the sun can result in severe phytophotodermatitis. Due to the growing prevalence of giant hogweed, the number of cases of H mantegazzianum-associated phytophotodermatitis in the United States is increasing. We report the case of a 27-year-old man who presented with a blistering rash on the neck and arms that developed 18 to 24 hours after trimming giant hogweed plants without photoprotection. A diagnosis of giant hogweed phytophotodermatitis should be considered for patients presenting with acute erythema and bullae in sun-exposed areas after exposure to the plant. Additionally, the public would benefit from education, especially during summer months, on identifying the plant and reducing phototoxin exposure to reduce the risk for phytophotodermatitis.