What is this grid of red dots on my chin?

June 30, 2018 10:43 AM

I have a grid of evenly-spaced dots on my chin that appeared at some point yesterday. They aren't from any injury or anything I am aware of. What are they? Pic and more after the jump.

Here's a photo of the mystery rash: https://500px.com/photo/264218915/img-by-chowflap

The only odd thing that happened recently is that I got my eyes checked on Thursday, and I had to rest my chin in one of those eye-checking gadgets. But the chin cup was smooth plastic.
Google searches come up with other people who have gotten the same thing and don't know what it is, a "dossier" which claims to have the answer but costs $10 to read, and various theories involving aliens and nanotechnology. The most rational thing I read was a rash called purpura, but why would it be in such an even grid? Help!

posted by chowflap to Health & Fitness (11 answers total)

Uh, I should add that the photo is NOT nsfw, and that the rash doesn't itch or hurt.
posted by chowflap at 10:45 AM on June 30, 2018

That grid is so regular. There has to have been something on that chin cup that you didn't notice at the time.
posted by chromium at 10:48 AM on June 30, 2018

One result I've found is from someone who got a grid rash, and the suggested cause was a pillow that has a rectangular grid of tiny holes in the fabric, through which the filling might be able to cause an allergic reaction. Apparently down and memory foam both can cause reactions.

But in this case I have to suspect it's something about the chin cup -- can you contact the doctor's office and ask them? Maybe the thing originally came with a label/piece of paper there, that was attached with adhesive dots, and they had to peel it off, and some trace of the adhesive is still there? Or maybe it gets sanitized with some device that applies disinfectant in that way?
posted by LobsterMitten at 10:59 AM on June 30, 2018

I get that on my chin when I rest my chin in my hand for too long. It's usually very symmetrical and like a grid just like that.
posted by ilovewinter at 11:32 AM on June 30, 2018

Did they wipe down the chin cup with an alcohol pad? Sometimes those can have a grid texture. Could that come in to play somehow?
posted by kittydelsol at 11:46 AM on June 30, 2018

I can't get a look at the cup itself from Google, but the position of your rash lines up perfectly, and I'd bet there was a grid of ventilation holes drilled into the bottom of the rest.

Then the question becomes whether these red dots are blood vessels which leaked, a skin reaction, or a superficial infection. I'd guess it was leaking blood vessels.
posted by jamjam at 11:49 AM on June 30, 2018

Sorry, I didn't mean to contradict your report that it was smooth plastic, but are you referring to the part your chin pushes up against or the support under your jaw, or both?
posted by jamjam at 11:54 AM on June 30, 2018

Press a glass on it, does it blanche? If not it is bruising.

I get this from leaning on hard things through robust fabric. Like leaning hard on a wooden chair back wearing a cotton chunky knit sweater.

So my guess is that you cupped your chin with something (possibly a hand with the sleeve pulled over it) and leaned on it for a while.
posted by intergalacticvelvet at 1:21 PM on June 30, 2018

I think I should call the eye doc's office on Monday. I don't remember there being holes in the chin rest, but maybe?
posted by chowflap at 2:05 PM on June 30, 2018

It looks like heat rash to me. I got some similar marks just today where my bra strap presses into my shoulder, after a long day in the sun.
posted by Lady Li at 1:33 AM on July 1, 2018

I marked this as resolved, though I still never discovered the cause -- the marks faded as quickly as a light bruise would. Weird!
posted by chowflap at 5:00 AM on July 31, 2018