Armpit Rash... Is It My Deodorant?

In my dermatology practice of more than 25 years, I have seen many armpit rashes. Itchy, red or chafed underarms, is your deodorant or antiperspirant to blame? Possibly, but there are other potential causes. It is worthwhile to figure out why you may have an underarm rash because with knowledge of the cause, comes the promise of relief. Rashes are annoying but even more so when they involve underarm skin, which is particularly thin and highly sensitive, a rash here can really get your attention. This delicate body part, the armpit (aka axilla, medically speaking), is a skin fold, where skin rubs against itself. Also, potentially irritating ingredients applied there do not evaporate quickly and “stay put” and also get trapped there under clothing. So the combination of sensitive skin area plus lingering of products we apply, equals a recipe for irritation. Add to that, we may not treat our pits with kindness when we shave, wax or use skin care products that can irritate thin skin.

Why Does My Skin Become Irritated In The First Place?

The skin’s most important function is its ability to guard us from outside offenders. The human epidermis/skin, is our biologic “wrapper”. Chemicals, microbes, ultraviolet light, are kept in check and our insides are well-protected thanks to our skin. While the skin does not allow easy access in, it also keeps us protected from losing vital substances such as oils and moisture to the outside. The skin’s ability to keep the good stuff in and the bad stuff out is known as its barrier function. Skin is our door to the world. So if skin is the door, then consider the skin’s microbiome as the security system. The microbiome is a collection of microorganisms, such as bacteria, fungi and viruses that reside on the skin surface in a delicate balance and provide a layer of protection and maintain the skin’s healthy status. This microbiome can be altered and when this occurs, rashes may be the result, not to mention infections, odors, and other deleterious outcomes. So paying attention this notion of barrier function and the common causes that lead to disruption of this harmonious skin protector, can keep aid you in keeping your armpits rash free.

Antiperspirant and Deodorant, What Is The Difference?

Before blaming deodorant or antiperspirant first understand the difference between the two.

Antiperspirant, found over the counter, is considered a drug which is regulated by the FDA and contains the active ingredient of an aluminum salt (e.g. aluminum chlorohydrate, aluminum chloride, aluminum zirconium tertachlorohydrex, among others). There are also prescription strength antiperspirants which contain higher concentrations of the aluminum active ingredient. Products that have aluminum are designed to block sweat from reaching the skin surface. The aluminum ingredient when it encounters skin cells and sweat, creates a physical plug in the sweat duct. This temporarily impedes the moisture from escaping the sweat gland through the sweat duct. This will keep the skin dry and helps us who are bothered by too much sweat causing damp skin and clothing. Deodorant is considered a beauty product and may be referred to as natural deodorant which will say “aluminum free” on its label because it lacks the active ingredient of aluminum and hence will not plug sweat ducts. Instead, it contains other ingredients such as baking soda, essential oils , and perfumes aimed at minimizing odor. Of note, natural or plant based doesn’t necessarily mean no side effects

Allergy Or Irritation, What Is The Difference?

Skin reaction: severe itching, red bumps, blisters and even oozing, localized to one specific area potentially signals an allergy, also known as contact dermatitis (think poison ivy rash). In this case the immune system is mounting a strong reaction to an allergen that the body recognizes as an offender. This type of reaction will tend to occur each and every time the body is exposed to the allergen.
Skin reaction: mild itching, chafing, flaking, and or dryness of the skin is more likely an irritation reaction also known as irritant dermatitis or irritant contact dermatitis, which is a more localized skin response that can be a one time occurrence. This type of reaction may or may not occur again and often subsides simply by discontinuing the irritating element. An irritation is also more likely in areas where rubbing or friction is impacting the skin (very common in the armpit where skin rubs against itself as well clothing all day).

Potential Causes Of Deodorant-Related And Other Causes Of Armpit Rash

Perfume. Pick up any deodorant and sniff, it likely smells nice. Natural deodorants and antiperspirants are almost invariably infused with fragrance. This is like an air freshener that uses a fragrance to trick your nose into smelling something pleasant and overshadow an offensive odor. This fragrance, while touted as natural, can mask body odor, but it can also cause irritation, allergy and rash. Allergists and dermatologists know all too well that perfumes can do this. Fragrances always rank at the top of ingredients at highest risk of resulting in skin allergy. Patch testing can help determine if you have a true allergic reaction on the skin, known as, allergic contact dermatitis and need to eliminate the use of specific fragrances. This concept is the reason for so many fragrance free alternatives on the market and why such brands target people with “sensitive skin
Dryness. Antiperspirants keep skin dry with aluminum. The aluminum creates a physical plug in the sweat duct that minimizes moisture not the skin of the armpit wherever it reaches. The intention here is to keep armpits dry, and sweat free, but this very action can go to extremes and make skin dry, flaky, itchy and cause a rash known as irritant dermatitis. Hack: put your product only on the moist part of the armpit. Avoid getting the antiperspirant on surrounding skin which does not produce sweat. Rule of thumb, only put antiperspirant to the hair bearing part of the skin not the perimeter. Focus the application.
Moisture. Just as dry skin can be the crux of a skin rash in the underarms, so can too much moisture. Allow the skin to dry thoroughly after a shower. Best way to do this... air dry. Use a fan or a blow dryer on the cool setting. Excess dampness can lead to yeast infections. If you get a recurrent rash, see your dermatologist. Heat rash, intertrigo and inverse psoriasis are all more common in moist skin.
Ingredients. Some people are sensitive to baking soda, preservatives, isopropyl alcohol and other ingredients found even in products labeled as “natural” or “for sensitive skin”. These ingredients can be particularly bothersome if applied immediately after shaving, waxing or other hair removal practices or after a strenuous workout. When trying a new deodorant and you know you have sensitive skin, use on small patch of skin first for a few days before using it all over the underarms.
Skin Irritation. Rubbing from clothing, shaving, waxing, scrubbing, towels, can all lead to underarm rash. Be aware that the skin in the axilla is delicate. Chafing can easily occur. Be kind to it. If you notice the skin is irritable, pink, itchy or you have just undergone hair removal like waxing or shaving, it would be a good idea to allow the skin to calm down before apply antiperspirant or wearing an itchy wool sweater. The goal is to avoid irritant contact dermatitis, the medical term for this type of rash.
Cleansers. Avoid harsh soaps by looking for body washes that do not contain perfumes, and are not actual “soap”, meaning they do not contain detergent ingredients (sulfates) or soap ingredients (alkali salts or lye) which not only degrease the skin (take away natural oils) but they have pH of 8-10. This higher alkaline level found in detergents and typical soaps is fine to use if you’ve got greasy or oily hands from mechanical work or the like, but for the thin underarm skin it’s a pass.
Infections. The underarm skin is host to resident bacteria which is part of its normal makeup. But with perturbation of this delicate microbiome may come influx of other more harmful bacteria, viruses or yeasts organisms. If your skin rash appears to have non-healing pimples, bumps, lumps, boils, blisters or pus filled lesions, it is time to see your dermatologist for evaluation and treatment. It is a good idea to seek healthcare options if your rash is painful. Don’t wait and avoid home remedies in this case.
Rare causes: There are some rare skin diseases that a dermatologist can diagnose for you if you have a chronic underarm rash. Do you have a rash that is life long or has been lingering for months or years and worsening over time? Get it checked out by a doctor for in person medical advice. Some conditions we dermatologists handle: Hereditary diseases causing rashes in underarms include Hailey Hailey Disease (aka Benign familial pemphigus) and Darier’s Disease.
Medical and Dermatologic Conditions Which Can Lead To Armpit Rashes
Acanthosis Nigricans
Eczema (aka atopic dermatitis, contact dermatitis, irritant dermatitis)
Hidradenitis Suppurativa
Psoriasis (aka inverse psoriasis)
Yeast infection

How To Avoid A Deodorant Rash

  • Use a ph balanced product and one which is free of added perfumes, such as Surface Deep Anti Odorant
  • Take a break from your current topical products and give your underarms a vacation from layering on stuff.
  • Seek deodorants that have soothing ingredients such as aloe vera, probiotics, essential oils .
  • Check the ingredient list and look for deodorants that are free of parabens and sulfates and
  • Detox the underarms (this is a trending practice but is not necessary if proper skin care is followed daily)
  • Be kind to your underarms which are under-appreciated. This skin is delicate and needs TLC.
  • If you notice a rash stop whatever you are using immediately. Do not shave or wax while the rash is present. Use soothing and fragrance free oils or ointment such as Aquaphor or CeraVe Healing Ointment for a few days at bedtime. If the rash persists or worsens, go to your doctor and in particular see your dermatologist.