How do you deal with an allergic reaction to a Dexcom sensor when you want to wear a CGM?
Many Dexcom users suffer from allergic reactions, which make it difficult for them to withstand a sensor for 7 days or more. These allergies sometimes come and go, or suddenly show up after years of use with no trouble. There is a large online literature of forums posts and blogs that discuss issues and potential solutions. The present series of posts summarizes some of these online reports.
Caveat: it should be clear to everyone that allergies are highly personal issues. So what works for someone certainly may not work for another – it is everyone’s responsibility to do thorough investigation and testing of any option presented here or anywhere else before using it as a remedy. As always, this post (or any other on the forum) does not constitute medical advice.
Allergy to what?
There are two particular sources of allergies in the sensor. The most often seen is the adhesive pad – Dexcom describes it as “a pressure sensitive acrylic adhesive coated on top of a polyester spun lace fabric. The housing is attached with cyanoacrylate glue from Loctite. Both are medical grade materials. There is no latex or bovine components in the adhesive.” The second is the sensor probe itself. Dexcom has mentioned the presence of a small quantity of nickel, a common allergen.
How to figure out if you are reacting to the sensor fiber or the adhesive
Conduct a simple experiment: wear a Dexcom sensor for a few days without injecting the probe. If you still react to it, you are allergic to the adhesive.
Note: there is a very small likelihood that you may be allergic to both.
CGM and pump allergies: similarities and differences
There are great similarities between CGM and pump allergies. For both types of medical equipment, the PWD may be allergic to the sensor probe or the canula, and the adhesive pad. So the general strategies are the same. But, for every PWD, because the materials in pumps and CGMs and the adhesives are not the same, the actual remedy will likely be different for your pump and for your CGM. In fact, you may react to one and not the other (or, hopefully, to neither).
Symptoms
As always, the symptoms vary. Some of them may be:
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red rash under the adhesive patch location, sometimes nicknamed “Dexcom rash” online.
This aggressive-looking rash should not be confused with the little red marks you get after lifting a Dexcom sensor patch a bit too fast. The red rash can look quite angry, as it does on little Caleb’s skin. Such a rash takes multiple weeks to heal, and makes it very difficult to find enough sites to rotate a sensor through. -
systemic reaction
The localized reaction to spread to the whole body, involving a puffy face, wheezing, skin breakouts in multiple locations, and, worst of all, the risk of anaphylactic shock. Little Henry suffered such a systemic reaction
. A systemic reaction can quickly turn deadly: you should seek medical attention immediately. -
Infection
Localized rashes easily get infected. Such infections can be very serious for diabetics: PWDs are susceptible to infections because sugar is a great medium to grow bacteria. They are also more vulnerable to the consequences of infection because of the out-of-balance BG resulting from medical stress. With PWDs, such infections can quickly become deadly. Isabella suffered from such an infection.
First thoughts
It should be clear to all that, for anything but the mildest symptoms, consulting a dermatologist could be really helpful, and may well be necessary (although, unfortunately, possibly not sufficient). If you are normally subject to allergies, before starting on CGM, it may be a good idea to ask the rep about your known allergies, and to sample a couple of sensors. For instance, our endo clinic offered, as a standard, the opportunity to wear one for a week.
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