Deodorant Rash: 3 Reasons Your Stick Is Messing With Your Pits & What To Do About It

First things first: Stop using whatever new deodorant you're testing out. Clearly, this isn't the outcome you're looking for. But beyond that, an armpit rash might be telling you that you're sensitive to certain common ingredients in deodorant. Here, what your armpit rash is trying to tell you.  

However, here are some of the most common allergens and irritants to look out for: 

Still more common in traditional deodorants or antiperspirants but common irritants are "the formaldehyde preservatives or formaldehyde-releasing preservatives," says Greenfield. The common culprits are quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, polyoxymethylene urea, sodium hydroxymethylglycinate, bromopol, and glyoxal. 

Baking soda's cause of irritation actually has to do with pH: Baking soda has a very basic pH, but your armpits (and, well, skin in general) is slightly acidic. Now, normally this is done on purpose: The idea is that when you increase the pH in the area, it will make an inhospitable environment for odor-causing bacteria. (As a very quick reminder, the reason for B.O. in the first place is because an enzyme in certain strains of bacteria interacts with your perspiration, resulting in a pungent smell.) Now, for some people, this causes no issue. For others, the change in pH (and therefore the skin microbiome) will cause a reaction. 

Finally, you may just find fragrance in general to be too bothersome sensorily. 

Usually, deodorant rashes can be self-medicated and are not cause for alarm. Obviously, as we've noted before, cease use of the deodorant once you start to notice discomfort or discoloration. You can apply a soothing cream or gel to temper inflammation and hydrate the area (see our list below), but ultimately, it may just take some time for it to fade: "Allergic or irritant rashes typically take about two weeks to fully resolve," says Greenfield. 

Now, if you find that it is serious (read: you're in consistent pain or the skin is fairly raw), you'll need to see the doctor. "Sometimes an area needs prescription medication for it to resolve in order to address the increase in inflammatory cells in the skin due to the reaction," says Greenfield. 

Don't worry; there are plenty of options to choose from. First up, if you're new to the natural deodorant world and you're reading this story because you suspect some of your irritation is from traditional preservatives, here's a good list of natural deodorants to start with. Now, if you suspect that your skin irritant is baking soda, you can find a plethora of baking-soda-free alternatives in the natural market too. As for fragrance and essential-oil-free, most brands offer options that don't include scent—or opt for a crystal deodorant. 

Rashes are actually quite common in the area. If it happens to you, stop using it immediately and try to suss out the irritant at hand. If all else fails, simply find a deodorant formulated for sensitive skin, sans baking soda, preservatives, and fragrances or essential oils.