After months of wearing the Dexcom G7 sensors, I have suddenly developed an allergy to the sensor adhesive. Two from the same batch caused angry skin reactions, so I pulled off the second one after only three days and replaced it using a hydrocolloidal barrier bandage. Dexcom is replacing it,and asked for the old one back.
Same thing happened to me when they changed the G6 adhesive long ago and added something I was allegic to. I have four more G7s from the same lot, manufactured in July 2025. Don’t know if it’s just some impurity in the adhesive or if they have changed the formula. So I may have to use the barrier bandage forever, or it may just be this batch. When they change they never admit it publicly, but it leaks out.
Anybody else who just started having the same problem? I know some people have been allergic to the G7 adhesive from the start.
I have tried the Libre3+ and its adhesive did not cause any reaction.
That’s frustrating! I’ve used Dexcom CGMs since 2009 and luckily have not experienced any allergic reactions. It doesn’t seem right when CGM companies hide behind “proprietary” excuses, especially when long-term customers present them with legitimate circumstances.
I developed an allergic reaction to Novolog insulin infusion after many months of continuous use. My symptoms were large raised welts at the infusion site. When I changed to another insulin, the site irritation and inflammation disappeared. Why was I able to use Novolog allergy free for many months before I developed symptoms? I wonder if your experience may be similar? Just an idea!
My allergies to Dexcom adhesive took a little while to appear. My allergist made it sound like repeat exposure can sometimes trigger an allergy (like developing allergies to local pollen 30 years after first exposure). My first 3-4 sensors of both the G6 and the G7 were fine, and then my allergy would start.
I hope whatever it is for you is temporary! They really should publish their adhesive ingredients… I don’t need a manufacturing manual or anything, just a list of materials used. “Proprietary” does hide a lot of helpful info.
I found this worth reading (diabetes is an allergy, read to the end
I’ve never had a reaction to stuff on my skin, other than the obvious Type 4 reaction when I sprayed myself with poison oak (diabetes is also a Type 4 allergy).
So… by analogy, we all know that there can be a long honeymoon until things get so bad that we suffer the pancreatic divorce. I’m guessing the same may be true for the Dexcom adhesive and possible a whole lot of other stuff; in other words it might take a long time to develop, like LADA.
That’s not so helpful; my solution to poison oak is to walk round it and if I have to cut it use an up-cut with the saw. The stuff flies away from me, but I still get it regularly.
Some people have problems with tegaderm patches (see TuD) but I suspect a good start is to first test tegaderm to see if you don’t get the reaction from that and, if you don’t whack one of the smaller patches (the G7 is only 35mm across at the widest point) and apply the G7 over it. I’m assuming you are not using Dexcom’s terminably unattractive overpatches which almost certainly have a different adhesive from the sensor.
I do think that they changed the adhesive. When I first started using the G7 I had to use the over patch because the adhesive did not last the full 10 days. It would start to peel and come off.
Starting several months ago, I no longer need to use the over patch. In fact, the adhesive sticks like super glue, to the point that it feels like I’m peeling off a layer of skin when I remove the sensor after 10 days!
Not recently, but these problems do pop up periodically. I might have reactions for a month straight, and then it disappears. I also see a lot of variability in adhesion efficacy over time.
