Skin Rash and Poison Oak

Asked August 17, 2015, 5:25 PM EDT

My boyfriend and I are both having skin rashes. He got his first, and then I got mine, which isn't as severe. We went to one dermatologist who said it was poison oak and prescribed a cream and steroid, but 5 days later, we are still getting outbreaks. The outbreaks are more mild, but still active. Some outbreaks are flat and just discolored (subcutaneous red marks) and others are like blisters. Not insanely itchy, only slightly. My boyfriend went to another dermatologist this morning for a second opinion, and that dermatologist said there is no poison oak in Colorado. I'm from Connecticut, and I have had poison ivy before, so I definitely know it's not that. We hiked in Lookout Mountain (Golden, Colorado) two days prior to getting the first signs of this skin rash/condition. I'm writing to you to ask you if you are aware of and can help us troubleshoot what kind of plant is known to exist at the elevation of Golden, Colorado (Lookout Mountain) that could disguise itself to look like poison oak, or if you know of any outbreaks that could help us manage our cases better. We also live on a lake in Arvada (Hidden Lake) and have been swimming/waterskiiing). There haven't been any other reports from residents about rashes on their skin from the lake, but I'm trying to give you all the information I can.

Adams County Colorado poison ivy

3 Responses

Poison-oak, poison-ivy and poison-sumac are all related plants in the genus Toxicodendron. Each has leaflets that look like those of oak, ivy and sumac, respectively To some extent, these names are regional and based on what species of Toxicodendron is found locally.
Western poison-ivy (Toxicodendron rydbergii) is fairly common in many parts of Colorado. There are large patches of it along the trails at Matthews/Winters Park in Golden and along Clear Creek. There are probably some patches to be found on Lookout Mountain.

Poison-Ivy has leaves in threes, somewhat resembling certain ivies. It is a woody shrub that can grow to perhaps 4 feet tall, depending on location and water availability. I would not be surprised at all if it were found at Hidden Lake. See attached photo.


Thanks for your answer and confirming the presence of poison ivy in the parts of Colorado I mentioned. Since one dermatologist diagnosed poison oak specifically, and the other dermatologist said there is no poison oak in Colorado, I was wondering if there is poison oak in the areas I mentioned. Thanks again.

Dermatologist #1 probably meant "poison ivy".
As I suggested, the terms poison ivy-oak-sumac are sort of interchangeable based on what part of the country you're from and what species of Toxicodendron are found locally.
The leaves of Western poison-ivy (Toxicodendron rydbergii) are somewhat variable in appearance, ranging from "ivy-like" to "oak-like" with lobes. It's understandable that dermatologist # 2 would say that there is no poison-oak in Colorado - Toxicodendron diversilobium is Pacific poison oak; Toxicodendron pubescens is Atlantic poison-oak; these species are found primarily in Pacific Coast states or East Coast States, respectively.
The one found in Colorado and Jefferson County is Toxicodendron rydbergii or Western poison-ivy.