Poison ivy, oak, and sumac plants (Toxicodendron species) often cause contact dermatitis due to soluble oleoresins (urushiols).
Contact can result in a severe, itchy dermatitis, which often persists for 10 to 15 days.
Prevention relies on recognition and avoidance of the plants, but many people are unaware of their appearance.
Immediate washing of the skin after inadvertent contact may prevent development of the allergic response.
First-line treatment is corticosteroids: topically for mild-to-moderate cases, and orally for severe reactions. Topical calcineurin inhibitors are an alternative option.
History and exam
Key diagnostic factors
- blisters and vesicles
- weeping, oozing, and crusting
Other diagnostic factors
- previous exposure
- breathing difficulties
- generalized erythroderma
- periorbital edema
- systemic contact dermatitis
- black-spot dermatitis
- occupation that involves exposure to relevant trees and plants
- outdoor activities
- domestic pets and livestock
- use of forestry equipment and machinery
- smoke from burning Toxicodendron species
- genetic susceptibility
1st investigations to order
- clinical diagnosis
Investigations to consider
- botanical identification
- black-spot test
- patch test
immediate treatment postexposure
chronic severe dermatitis from repeated exposure
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