Outcome is generally excellent if further exposure is avoided. Sensitivity may diminish with time if re-exposure is avoided. The dermatitis usually settles in 7 to 15 days but may persist for 6 weeks. Poison ivy, oak, and sumac antigen will cross-react with other Anacardiaceae species, including mango, cashew, Japanese wax tree, and Japanese lacquer tree.[1]Rietschel RL, Fowler JF, Fisher AA. Contact dermatitis. Baltimore, MD: Lippincott Williams & Wilkins; 2001.[2]Guin JD, Beaman JH, Baer H. Toxic anacardiaceae. In: Avalos J, Maibach HI, eds. Dermatologic botany. Boca Raton, FL: CRC Press; 1999.[3]Zug KA, Marks JG. Plants and Woods. In: Adams RM. Occupational skin disease. 3rd ed. Philadelphia, PA: WB Saunders Company; 1999.[4]Dannaker C, Maibach HI. Poison ivy and oak dermatitis. In: Lovell CR. Plants and the skin. Oxford, UK: Blackwell Scientific Publications; 1993.
Cross-reaction with other non-Anacardiaceae may also occur; these include Ginkgo biloba and Grevillea species.[1]Rietschel RL, Fowler JF, Fisher AA. Contact dermatitis. Baltimore, MD: Lippincott Williams & Wilkins; 2001.[2]Guin JD, Beaman JH, Baer H. Toxic anacardiaceae. In: Avalos J, Maibach HI, eds. Dermatologic botany. Boca Raton, FL: CRC Press; 1999.[3]Zug KA, Marks JG. Plants and Woods. In: Adams RM. Occupational skin disease. 3rd ed. Philadelphia, PA: WB Saunders Company; 1999.[4]Dannaker C, Maibach HI. Poison ivy and oak dermatitis. In: Lovell CR. Plants and the skin. Oxford, UK: Blackwell Scientific Publications; 1993.