Wednesday, June 23, 2010

Black Spot Poison Ivy

I love learning something new in medicine and this was a new one for me...black spot poison ivy.   Poison ivy (also known as rhus dermatitis) is a common contact allergic dermatitis.  Like poison oak and poison sumac, the chemical that causes a reaction is called urushiol.  When this plant sap touches the skin a pruritic (itchy) red rash appears with little blisters that are often in a line.

Black spot poison ivy is the same urushiol but in humid, warm conditions it is oxidized by lactase from the skin and turns into a dark black lacquer color.  It is an uncommon presentation because usually the sap is diluted by perspiration and never turns black.

Poison ivy/oak is more common in the summer and I treat lots of cases in Northern California because it grows like a weed.  The worst cases are when someone tries to burn the plant and inhales the resin.  Treatment of black spot poison ivy is the same as regular poison ivy.  Washing the skin, clothes, and all contacts area immediately is critical.  Severe cases may require systemic corticosteroids and rebound rash is common.


(Image from Consultantlive)

16 comments:

Kellie said...

Thanks for posting this, it is good info. to know, but then all of your posts are.

Toni Brayer, MD said...

Thank you, Kellie

Divine Ms. M said...

Thank you for this article. I have regular ivy near my patio growing wild and thought it might be poison ivy but for the lack of three leaves. I searched Google and this article came up. Thanks to this blog I identified true Poison Ivy growing nearby that I would have missed had it not been for this post. Here's to a non-itchy summer!

Anonymous said...

Hello. My son is 2.5 years old and has black spot poison sumac. Severe case by far. I was trying to google "black spots on skin" and came to this. Thank you so much! I knew what I saw was VERY different than anything I've ever heard of but when I tried to explain it, no one would believe me! My first thought was that he got into some black permanent markers b/c it wouldnt' wash off. With a closer look I realized it was actually a PART of his skin!! I was worried but more curious b/c he didn't really seem to care or notice it was there. About six days later it started turning reddish pink where black was, then lots of broken sores and rashes and itchy bumps....we are still in presentation stage: after two weeks, STILL only getting the reaction to come out of his body. It has to burn itself out of his system. The longer it takes to present itself as a poison sumac/ivy/oak rash, the longer it lasts. It's a very dangerous reaction b/c it hides in the black lacquered markings deep in the skin. When you've never heard of it and you don't know what it is, you don't think think it's a poisonous reaction. By the time I realized, it was way too late. It's not contagious but it IS easily transferable on clothes and other skin if scratched. It's a difficult thing to deal with! It was 32degrees fehrenheit when we were out and he came across it. VERY humid. But it's typical for that temp where I am so it was nothing to be out in the heat like that. Normally sweat glands help fight off the poison but my son had two terrible things going against him. 1. Humidity 2. very tiny if existent, sweat glands. Perfect host for the chemical reaction to take place :( I'm worried, I hope he gets out of it without scarring :(( Our second visit to doctor was today. Thank God, by now I'm well versed/knowledgeable in this stuff now. Oh one more thibg, once it happens, it gets much worse the second and third etc. time around...

Anonymous said...

Thank you for posting this! My husband just got this and we could not figure out what it was. Started off with a few flat black black colored marks. The next day some of them became a raised scab. And finally 3 days later it has started to look like "normal" poison ivy. Both of us have had poison ivy, oak and wood before (we live in south Florida) but never had a reaction like this!

Anonymous said...

Good article!

I had this on my face last summer, and I thought it was the reaction of the face cream I used with a small posion ivy lesion. I garden around the vines and they occasionally poke me with their ends. It was so black it looked like a marker spot imbedded in the skin.

Well now I have a very bad, big lesion from gardening 2 days ago. It is so locally swollen and thick and warm that I'm going to the doctor tomorrow because I think it is infected (very dangerous potentially). It's like an abscess with the big very black spot of this form of PI right in the middle.

Maybe black-spot poison ivy is more susceptible to infection? I'll find out in the morning, but y'all be warned just in case!

Anonymous said...

Did you get a diag for your condition? My Mom (83yo) has been treating for BSPI for 2 weeks and is still having more lesions appear. Have been to MD 2x, ER 1x, and DermaDoc 2x. I am very interested in hearing your results. Thank you so much.

Anonymous said...

I've never had poison ivy, so I was suprised to be diagnosed with black spot poison ivy. The dermatologist said it's pretty rare. Ten days in, and it's just starting to itch. I mean ITCH! I guess that's normal?

Anonymous said...

My son and I both have black spot poison ivy. The first day he got it, it looked like these black marker spots on his face and neck. The next morning the spots had changed slightly in color. 24 hours later he had red, itchy bumps around the spots. Three days later, I had broke out in the red bumps, then blisters. It has been two weeks and we both still have it. It has gotten better, but now my neck and chest has red blotches, with a burning sensation. Not sure why, but I can't wait till this is over.

Anonymous said...

I just left the Er thought I had some freaky flesh eating disease. So scary looking. . .they put me on steroids and sent me home. It's been ver humid who knew?

Ivy said...

Jewel weed helps with itching.

Anonymous said...

I see there has not been many comments in 2014 on black spot poison ivy. This is the first time I have ever heard or seen this stuff. My daughter just went to the ER (because it is Sunday)with this stuff. She has it on her lips and some on her cheek. She was hugging on her cat last night. The cat goes in and out of the house. Daughter was broke out with a little rash and the black lines. First thought it was some of her make-up along with the poison ivy. I got some mineral oil to remove the black marks, but did not come off. Did some checking and found out it was black-spot poison ivy. Just really worried with this on her mouth.

Anonymous said...

My 7 year old daughter was just diagnosed with this. It took 3 trips to different doctors before they figured it out, including children's hospital ER. The first told me it was a spider bite, then the doctor at the er said he was stumped and had no idea what it was! Finally we got the correct diagnosis, and after seeing these pictures, we realized that is exactly what it is. It is on her face, she had been playing outside and it was very humid. They gave her a steroid shot and her rash already looks so much better. They said it will take months for the black to go away though. Thanks for this article!

Toni Brayer, MD said...

You are very welcome.

Teri said...

If I have black spot already, and now the area around the spot has blisters, what should I do??? Am worried...😢

Teri said...

How do keep black spot poison ivy from spreading if blisters start forming???