MDMA allergies

I known someone who has recently started ingesting mdma, and has used it three weekends in a row since his first dose. Each dose has gotten a little larger then the last with the first being under a tenth and the last being .18 almost two tenths. On the final experience the next day he noticed that he had developed a rash on his chest, and has been wondering ever since if this could have been an allergic reaction or something else.
Please give all advice and knowledge that you may have on the topic.
Thanks!

Here's my experiences with mdma and hives:

1: 2 green rolls, random kid my buddy knew, terrible time, 3-day hangover, had hives (speed?)
2: Unknown amount Buddy from the airforce, amazing time, afterglow
3: 100 mg "Gas Mask" from the club, amazing time, 1-day hangover, (methylone?)
4: 100 mg "Gas Mask" from the club, amazing time, 2-day hangover, had hives, never touching his stuff again (methylone?)
5: 60 mg Silk Road A, terrible time
6: 160 mg Silk Road B, BEST roll, depressing comedown, had hives
7: 200 mg Sheep Market A, decent time, had hives
8: 80 mg Sheep Market A, mediocre time.

I haven't touched it in over a month and I'm still randomly getting hives, although less and less.

By hives, I would get maybe 3-4 small dime-sized ones that itched for about 40 minutes and slowly faded.
Once I had a bunch of "microdots" on my right arm that persisted for an hour, kinda freaked me out.

Keep in mind, I eat organic, gluten-free, mostly vegan, etc. I exercise daily, vaporize primarily, and consider myself quite healthy--I would have no other reason to attribute hives to. But because it's not a 100% thing, I really don't know.

Its not something I've seen but its possible. Or it could be a cut.
To the second poster what vendors products were you using? The fact that you had a few amazing times with no hives is what is puzzling to me.
Maybe preload with a long acting antihistamine for a few days before and take jt for a few days after.

I couldn't tell you the vendors--my partner, S, takes care of that end of me. He's much-more intelligent than I am and I entrust him to

Yeah, I was REALLY confused by the "clean stuff" giving me hives. I even mentioned it to S and he was very puzzled--he had ingested a gram of the same product in one night, with no issue. S has rolled less than 5 times. He's a big lucy fan.

Obviously I didn't intentionally take anything cut and my ignorance when I first started didn't help. S put me on the right-track.

Quite unusual. I'd probably skip it altogether but taking something like zyrtec for a few days before and after might do the trick.
The fact that you haven't always gotten it makes me wonder if its an impurity. Even 98% has 2% impurities.

Id get a test kit...and benadryl.
Environment could be the cause..rolling at a rave with glitter and fog machine dust ect...rubbing oneself(haha) while rolling can produce rashes,I got one on my shoulder from some fairy chick that wouldn't leave me alone cause I fed her too much molly..maybe her perfume?lotion?..ther are a lot of factors,but ill all my days I've never seen nor heard of mdma allerys..but I'm certain it can happen..I seen a documentary where this girl was allergic to semen..for ral,I'm not trying to joke..using that as an example..so if something that natural can hurt someone,I'm sure a chemical can...hope you figure it out so you can keep rolling when you want!