Hello @karenamara, Welcome to Mayo Clinic Connect. You will notice I changed the title of your discussion a little to hopefully give members a little better idea of what the discussion is about. I would like to invite @cld1577, @gardeningjunkie, @dazlin, @gloriajean, @barbarn and @texasduchess to join the discussion and offer any suggestions they may have.

@karenamara, Has your boyfriend seen a dermatologist about the rash?

no, he hasn't seen a doctor. he thinks it's unimportant since "he's still alive" and it's been happening for years. but i'm curious to know what it is

I certainly understand why you are curious karenamara. I've never seen any eczema rash like his photo; it's so symmetrical. Also most eczema itches and may also be painful. It doesn't appear to scab. . Does it come and go? It looks more like he is leaning against something that leaves an imprint or was run over by a tire! Does he sit in the same chair he did since he was a teen? Very peculiar.

I Googled grid shaped rash and looked at images. There were quite a few pictures of people with similar rashes. No one seems to know what the cause is. Also no itching or pain. At least he’s not alone🙄

i also thought he was leaning on something but it isn't from that. sometimes he just wakes up like that and it takes about a week to pass.

strange!

babbs- your comment caused me to search the internet and yes there are many examples that look just like what karenamara's boyfriend gets. We know there must be a cause but It makes me think of alien visitations.

That cracked me up – in fact quite a few people who have this type of rash believe that. One lady said if they come back to take another look at her, could they please drop her off at Starbucks on the way back. I was going to include that in my post, but after my woo-woo lady post, I figured you'd all think I've totally lost my mind. One dermatologist reports a similar grid type rash which he believed came from a post exercise massage with a soft ball. https://www.cureus.com/articles/5103-softball-petechiae-a-novel-cutaneous-finding-in-a-patient-participating-in-post-exercise-massage. Frankly, I think the alien explanation is more likely than the softball explanation 🙂 There are several articles of a similar rash caused by a puss caterpillar or "asp," Megalopyge opercularis. These rashes are reported to be extremely painful. While the person asking about this said her husband's rash isn't painful or itchy, it's possible that the first incident occurred when he was young and was painful then. There are discussions about this type of rash on Reddit, as well. A lot of alien talk there, too. As in the case of our GD diagnoses – the answer could be anything.

babbs I am impressed with your puss caterpillar theory. I looked at a few photos of the puss caterpillar rash and the grid is so similar! The photos I saw of the rash were framed around the grid, but these photos were of recent victims. The overall size of the rash was similar. We know that even with the same type of eczema our symptoms manifest slightly differently from each other and can change as time goes on.
Question for karenamara. Does he live or has he visited the southern states? It has a wide range, the west end and all though Texas, north and east though Nebraska, Missouri and all though Florida and east to Maryland. This caterpillar lives in common shade trees and shrubs around homes, schools and parks.
What I didn't find was any information about this being a chronic issue. From all I read the rash takes weeks to heal but no where was a recurrence mentioned. Still, perhaps there is a strain of this caterpillar or a similar one that causes recurring symptom.
I am disappointed that this is blowing holes in my alien theory I even looked up Morse Code to see if the pattern was a form of communication. Dot, space, dot, space. If it were dot, dash, dot, dash repeated that would be a a a a a-perhaps for Alien!
I think those of us with eczema have the right to be crazy. Those who haven't dealt with our misery don't understand how long time can be between the seconds while laying in bed on fire and itching.
Words I live by credited to Waylon Jennings country song, I've Always been Crazy,
"I've always been crazy, but it's kept me from going insane". His words make sense to me.

he hasn't visited southern states, we live in israel

Have you Googled Puss caterpillar or other caterpillars that live in Israel?, Although a arid country you have farming and tree and shrubs around homes. Did you google the photos we have discussed showing photos of these caterpillar rashes that resemble the photo you sent us?

i can't find any info on the web about that kind of caterpillar in israel, or any other kind that causes a rash like my partners

the only moth/caterpillar i did find information about is called Thaumetopoea but it causes a rash that looks different

What a mystery.

That was my first thought also. Does he sleep without a shirt? I've seen a lot of memory foam mattresses that have a similar pattern or cover. If it's always when he wakes up, I would be looking very close at the surroundings, especially since there is no pain or swelling, raised bumps, etc..

it's definitely not a pattern from pressing against a net. it appeared on his back for the first time when he was a teen in psychiatric ward. and it still continues to happen today at age 26, 10 years later