Allergic Reactions at Sensor Site

I've used a Dexcom for 3-4 years at this point, and it's a vital part of my BG management. However, in the past couple of months, I've started developing an allergic reaction of some type at the site of the sensor. By the end of the sensor's life, the site area is red, inflamed, itchy and irritated. After the sensor is removed, the skin under the sensor is red, inflamed, bumpy and very itchy (not the area under the tape or adhesive, which is fine. It's just the skin under the sensor plastic/transmitter holder that is inflamed).

At the same time, I've started having a ton of sensor failures on the G4, which until recently was infrequent. Dexcom is always wonderful and they replace the failed sensors. However, I really just want my G4 to work!

I've begun taking Benadryl at night, which seems to help some. Also, after I remove the sensor, I apply a prescription steroid cream to the site, which helps contain the itching. But, it takes 3-4 weeks for each sensor site to fully heal. My abdomen is oh, so attractive!

Has anybody else experienced this? It's really frustrating and impacting my BG control and peace of mind. It's gotten to the point that I frequently just go without and use BGM alone, albeit I test 10-12 times a day like I used to test prior to CGM. The combination of the sensor failures, more frequent inaccuracies and skin irritation just makes the effort seem not worth it. However, my BG control suffers, which is not ideal.

Any thoughts/insights are very welcome. Thanks! - Anna

Two thoughts come to mind.

1. It might indeed be an allergy. If it is an allergy it may be to the glue that bonds the rigid part to the fabric dressing. You might try the "sandwich" technique used for insulin pump infusion sets where a layer of something you aren't allergic to like Tegaderm or some similar dressing is put on the skin before the set. Also the various iv prep/skin prep wipes put a layer between you and the sensor. Sensor manufacturers tend to recommend against these steps as anything but skin might damage the sensor, but it sounds like things aren't so good now.

2. It might be mechanical factors. The fact that it is limited to the more rigid part of the patch suggests this might be the case. If you pull/stretch the skin as you insert the sensor, then that skin that sticks to the rigid part of the sensor will continue to be stretched until you remove the set, though the fabric part can relax. Try inserting without pulling or stretching the skin.

Finally, if the transmitter/sensor sled are catching on clothing, that might cause a problem. A layer of Tegaderm over everything can cover sharp edges that catch on things.

Yes…I have allergoc reactions to both the dexcom adhensive and all insets adhesive. I use lots of skin tac and then have a cream to put on the site after I remove them. I cannot wear the insets for longer than two days because I cannot stand that itch and the rash is like a third degree burn. Dexcom is not as bad and I can tolerate the itch. If I dont use enough skin tac, I will have the rash for days. It makes rotating sites a little tricky.

Our daughter has exactly the same reaction as you. The red footprint is of the plastic, not the tape. However she is allergic to most tapes too. Here is our procedure that works pretty well.
Our daughter is highly allergic to most tapes (paper hypoallergenic tape is the exception, and we use it sometimes around the edges of our pod and insertion set). And she seems even more allergic to the plastic components of the Omnipod and Dexcom insertion set (judging by the footprint of the rash). Previously her rashes have even been bleeding and very ugly. Now her skin is baby-smooth, except for a small nipple where the insertion occurred, probably due to a reaction to the cannula. Here is our current procedure for dealing with rashes from our Omnipod and Dexcom.
Omnipod: 1) alcohol wipe and dry, 2) hydrocortisone spray (over the counter Rite Aid) and dry, 3) Coloplast wipe (Amazon) and dry, 4) Skin-Tac wipe (Amazon) and dry, attach the Omnipod. Dexcom: repeat the Omnipod procedure, then 5) J &J Tough Pad ( is cheapest). Inject the sensor directly through the Tough Pad. The procedure tends to lower adhesion, so in order to help with adhesion, we use liquid Skin -Tac and soak the adhesive pad on the Omnipod and Dexcom using the included sponge applicator before a bath or swimming.