Poison Ivy, Oak and Sumac
Poison ivy, poison oak and poison sumac grow in wooded or marshy areas throughout North America. Allergic contact dermatitis is commonly caused by these plants that have a sticky oil called urushiol that cause an itchy, blistering rash upon contact with the skin. The oil sticks to skin within minutes of exposure and the rash develops over days. Thus, if you suspect contact, wash the area with lukewarm water and any affected clothing in hot water as soon as possible.
Red, raised blisters and bullae typically appear within 12-72 hours of contact with the urushiol resin, and peaks within 1 week, but can last as long as 3 weeks with lesions appearing gradually over this time. The rash is not contagious from person to person, even if there is exposure to the fluids in the blisters; however, resin that remains on clothing or animal fur can be contagious and continue to spread the rash. Further, if eyes and face are affected, significant swelling may occur and require oral steroids and antihistamines to stop progression of symptoms.
Based on the severity of your skin’s reaction, your dermatologist may prescribe a topical or oral steroid to reduce inflammation, or an antibiotic if the area has become infected.