Mystery mark stains seat! Blue butt print upon the tainted throne!
June 27, 2014 10:37 AM   Subscribe

This morning, I was surprised to see the clear imprint of my wife's butt and thighs in a bluish tone on our white melamine toilet seat. Is the actual chemistry known here, and what should we do to avoid this in the future?

There were faint bluish marks on a bath towel as well, and this afternoon when we discussed it, she found that a device she wears under her clothing for medical reasons had a piece of tubing that had taken the color as well.

Dr. Google informed me that this specific issue is most commonly seen in pregnancy, something that is out of the question here (due to age and the reproductive system in question) but that it is also associated with a smaller set of both male and females under maddengly vague circumstances. For these folks, often cited elements include "stress", the ingestion of b-complex stress vitamins, and the use of progesterone. Less cited elements included specific drugs used to treat a variety of intestinal ailments such as Crohn's. Rather than corral all the links here, I leave them as an excercise for the reader.

There was literally no well-sourced scientific or medical information available in the search result, which I found aggravating and incredible. Clearly this is a well-documented event in some pregnancies, and yet, there appears to be no scientific research or analysis easily located. Eventually I found a vague diagnostic condition, pseudochromihydrosis, but the information presented there was of limited utility and implies a skin-based bacterial infection rather than a sweat-based chemical reaction independent of an infection.

After carefully reviewing her day for dietary changes, we found a possible culprit: two 15-oz Starbucks Double Shot energy drinks. We also note that she has recently changed to a draconian work schedule requiring her to rise at 3 am and that she has been taking b-complex vitamins.

The color on the toilet seat does not bleach out. It is a pale indigo, the color produced by the chemical interaction of iodine and starch. My operating assumption is that it's likely to actually be produced by this reaction.
posted by anonymous to Science & Nature (19 answers total) 4 users marked this as a favorite
I had a very similar thing happen when I bought a new pair of jeans - the indigo dye rubbed off everywhere. I'd check for colorfastness in clothes before assuming there's some weird chemical reaction going on in her skin.
posted by Metroid Baby at 10:43 AM on June 27, 2014 [39 favorites]

Agree with Metroid Baby - any new underwear or jeans? Same thing happened to me with the indigo dye.
posted by barnone at 10:45 AM on June 27, 2014

ha!! This actually happened to me yesterday evening, and I had a holy fucking shit I am exuding blue moment before I realized: I was wearing newish jeans that had gotten damp.

Put some rubbing alcohol on some toilet paper and wipe it off. That should help get the dye out.

99.3% sure your problem here is just blue jean dye.
posted by phunniemee at 10:51 AM on June 27, 2014

Jeans + lotion do that sometimes. Even jeans that have been washed a few times.
posted by mercredi at 10:51 AM on June 27, 2014 [1 favorite]

Yeah I've totally stained my legs slightly blue from cheap jeans (and it took several showers to finally wash off completely). The jeans did have a label warning that they could potentially leave blue dye on light colored furniture.

So no, your wife isn't suddenly turning into an Avatar-like creature.
posted by littlesq at 10:55 AM on June 27, 2014

Yes, most likely new jeans.
posted by ktkt at 10:56 AM on June 27, 2014

Yup. Even old jeans do this to me.
posted by three_red_balloons at 10:58 AM on June 27, 2014 [1 favorite]

Came here to say "indigo dye + jeans!". Realised I was way late, left embarrassed.
posted by Leon at 10:59 AM on June 27, 2014 [4 favorites]

Probably jeans! Also, try a quick swipe of a little nail polish remover on a cotton ball, if nothing else takes away the blue stain from the plastic. Definitely test in an inconspicuous location first just to make sure there is no weird reaction. A lot/pouring it on will melt the plastic/finish, so just use a little and see. Nail polish remover has saved me many a thing that I thought was irreparably stained!
posted by amileighs at 11:07 AM on June 27, 2014

This has solved a mystery in our home!
posted by under_petticoat_rule at 11:09 AM on June 27, 2014

for what it's worth, this has happened (repeatedly) to me and i have no idea why, except i know it's not jeans. like you, through googling, i got a lot of really vague answers. it's interesting that some find it related to their crohns medicines, as i have ibs-c and take a twice daily medication for it. also like you say, bleach (and lots of other cleaners/alcohol/vinegar&baking soda) didn't remove it.
posted by nadawi at 11:12 AM on June 27, 2014 [4 favorites]

There is such a thing called chromhidrosis, which is colored sweat. But if your wife was sweating blue from her rear-end, she'd probably have blue-stained armpits on her clothes, and a fine spray of blue on her forehead. But I definitely lean towards the far less exotic explanation of bluejeans.
posted by Sunburnt at 11:17 AM on June 27, 2014

i also don't have colored sweat - this only appears on the toilet seat - and it seems more prone in some seasons than others. i just moved and it hasn't shown up at my new apartment yet, but if it does i'll try to pin down some specifics. if you want to memail me, i can memail you details if it comes up again.
posted by nadawi at 11:23 AM on June 27, 2014 [1 favorite]

Is it possible a cleaning agent has not entirely been removed from the seat in question that has reacted with the sweat (or a component of the sweat) to create the color?
posted by NoDef at 11:38 AM on June 27, 2014

This article suggested that the patient in question had pseudochromhidrosis and some kind of skin bacteria was interacting with the sweat to make it blue. Sometimes oral antibiotics are used, but this doctor suggested that an antiseptic soap was enough to remove a bacteria on the skin, and for these two patients, it worked. Something to think about? Think Like a Doctor: The Blue Girl Solved!
posted by barnone at 12:30 PM on June 27, 2014

Mod note: From the OP:
The blue-dye suggestions are absolutely not correct. I apologize for not spelling that out; after a day of link trawling it had escaped my mind that most folks would see that as the obvious solution.

This is not associated with new jeans or clothing dye. The imprint is perfectly even and shows no streaking or concentration and has slightly faded over the past day possibly due to light exposure. If it were dye, it would have been observed on the front of her thighs as well as well as in the shower. Instead, the color occurred only where she contacted the toilet seat and therefore was unobserved by her. If the color occurred as a result of an oxidation reaction, it's even possible that the color had not developed at all until she had left the room.

Please see nadawi's comments for an example of another person with a similar experience."

If it were possible, I would even ask the blue-dye suggestions be removed, as they give the mistaken impression that the answer may have been discovered.
posted by mathowie (staff) at 1:30 PM on June 27, 2014

I don't know if your comments about pregnancy being not an option means she has had a hysterectomy or what, but could she get her hormone levels checked anyway? Might be increased progesterone due to a cyst or some other abnormality and not specifically pregnancy. Could be a combo of that and the energy drinks or menopause hormone fluctuations.
posted by MultiFaceted at 2:39 PM on June 27, 2014 [1 favorite]

Mod note: Another update from the OP:
UPDATE: sorry for threadsitting - I dropped nadawi a line and some brain fruit popped out.

One thing I'm wondering about a bit is if it could be some sort of photochemisty, similar to the photochemistry in the delightful science toy Sunprints, where the blue coloration actually does not appear until the paper is immersed in water.

In this thesis, the chemistry for the photo reaction is carried in the sweat but not catalyzed to turn blue until it a) is transferred to the toilet seat and b) exposed to light. This would explain the apparent delayed observation of the print. I suppose changes in temperature could also account for the catalysis, or maybe both light and temperature.

hm, the chemistry in the sunprint process is cyanotyping:

ferric ammonium citrate and postassium ferrocyanide are the active components. water and light are required for the oxidation and photocatalytic reaction that sets the blue color for the exposed areas of the print.

Therefore the questions are a) what aspect of this chemistry is the product of my wife's biochemisty and b) what aspect may be environmentally attributed?
posted by LobsterMitten (staff) at 3:06 PM on June 27, 2014

Interesting - seems like this is a thing. OP: Have you read this comment? It fits with your cyanotype/photography theory.

After much Googling my theory is that the ionized silver anti-microbial coating on the toilet seats is being turned into silver salts by sweat during pregnancy (Probably by higher acidity caused by sweating out something: excess proteins, vitamin supplements, etc.). These silver salts are then exposed to light as in a gelatin silver print and over an hour or so are resulting in an even deposit of microscopic deposits of silver as a film across the seat. The process being similar to what happens in argyria, a blue-grey pigmentation of the skin caused by absorption of silver into the body. The microscopic deposits of silver will not return to their prior state and are not going to be bleached away. You would have to use acid so they are likely to be there for good. For non silver anti-microbials there is a dye called bromophenol blue which is a absorbed by some of the coatings but I prefer the silver deposit theory as I suspect silver anti-microbials are more common on toilet seats.
posted by suedehead at 3:12 PM on June 27, 2014 [2 favorites]

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