Common Causes of Armpit Rash and How To Solve Them

Ever found yourself in a scratch-athon, courtesy of an armpit rash? It’s not just you. But before you start pointing fingers at your deodorant, let's dive into the top reasons your pits might be pitching a fit, and how to strike out those rashes for good!

THE UNCOMFORTABLE TRUTH ABOUT ARMPIT RASH

Armpit rashes can seriously mess with your day. They can be itchy, painful, and just plain annoying. Here are the key reasons you might be dealing with an armpit rash:

1. Heat rash 

One common cause of underarm rash is heat. When you sweat a lot, especially in hot weather or during intense workouts, your sweat can get trapped in the glands. This can lead to tiny, itchy armpits with red bumps that feel uncomfortable and irritated. 

2. Friction 

Tight clothing and repetitive movements can cause friction, which can lead to rashes. If your shirt is too snug or you’re constantly moving your arms, the rubbing can irritate your skin, creating redness and discomfort. Wear breathable fabrics and roomier fits to avoid that “burning” feeling. 

3. Candida (armpit fungal rash) 

Bacteria and fungus thrive in warm environments, and your armpits are basically a tropical getaway for them. This can lead to an armpit fungal rash, often caused by Candida, a yeast infection that flourishes in moist areas.¹ The result? Itchy, red, and sometimes painful patches under your arms. To help prevent flare-ups, keep your underarms clean and dry, and use products designed to minimize moisture. 

4. Allergies 

Sometimes, the culprit of an armpit rash is the products you use. Deodorants, soaps, detergents, or even fabrics can cause allergic reactions, which can leave you asking, “I’ve just switched products, is that why my armpits are red?” If you’ve recently tried something new and noticed irritation, consider making a switch. 

5. Shaving 

Improper shaving techniques, or using dull razors, can cause tiny cuts that irritate the skin and make your armpits feel raw or itchy. Always shave in the direction of hair growth and use a sharp, clean razor. 

6. Eczema 

Eczema is a chronic skin condition that causes dry, itchy, and inflamed skin—even in the armpits.² Moisturize and stick to gentle products to help manage flare-ups. 

7. Psoriasis 

Psoriasis can cause red, scaly patches of skin in your underarms.³ If deodorant and home remedies aren’t cutting it, consult a dermatologist for treatment. 

8. Dermatitis 

Dermatitis happens when your skin reacts to an irritant. It can leave you with itchy armpits and red patches. Identifying and avoiding the trigger (like a harsh deodorant or laundry detergent) is key. 

PREVENTION AND TREATMENTS FOR ARMPIT RASH 

When you’re dealing with itchy armpits, wondering “why are my armpits red?”, or trying to avoid the discomfort of an armpit fungal rash, prevention is your best defense. The good news is keeping your underarms healthy and irritation-free doesn’t have to be complicated. It just comes down to a few smart choices. 

 

Keep it clean 

Daily hygiene plays a huge role in avoiding armpit rash. Wash your underarms with a mild cleanser to help remove sweat, bacteria, and excess oil—the stuff that can lead to rashes and fungal growth. After washing, it’s important to dry your underarms thoroughly before applying deodorant or even getting dressed. Trapped moisture creates the perfect environment for irritation and fungal infections. 

Wear breathable fabrics 

Your clothing choices can make or break your comfort. Fabrics like polyester and nylon tend to trap heat and moisture, which can leave you with itchy armpits and redness. Natural fibers like cotton or linen, on the other hand, are breathable and allow air to circulate, which helps to keep your underarms cool and dry. The less sweat and friction your skin has to deal with, the lower your chances of developing a rash. 

Mind your shaving routine 

Shaving is a common culprit behind armpit irritation. Using a dull razor or shaving against the grain can cause tiny cuts and abrasions, which can lead to inflammation and sometimes even infection. To prevent this, always use a sharp razor and shave in the direction of hair growth. Pair this with a soothing, fragrance-free shaving cream to help protect your skin barrier. And remember, avoid applying deodorant immediately after shaving, as freshly shaved skin is more sensitive and prone to redness. 

HOME REMEDIES FOR ARMPIT RASH

Already dealing with itchy or red armpits, or facing the discomfort of an armpit fungal rash? Don’t worry—you’ve got some simple, soothing options that can bring relief right from home.  

• Cold Compress: Apply a cool, damp cloth to your underarms to help reduce itching, redness, and swelling. The cold temperature constricts blood vessels, which helps ease inflammation and brings quick relief to irritated skin. 
• Aloe Vera: Known for its natural cooling and anti-inflammatory properties, aloe vera gel is a gentle way to calm down irritation.  
• Coconut Oil: This isn’t just a moisturizer. Coconut oil is also naturally antibacterial and antifungal. Apply a thin layer to help hydrate your skin, fight unwanted microbes, and prevent further irritation. 
• Oatmeal Bath: Colloidal oatmeal is a classic remedy for inflamed or irritated skin.⁴ Adding it to your bath can help calm down itchy armpits and reduce the urge to scratch. The natural compounds in oatmeal form a protective barrier that locks in moisture while soothing irritation. 

 

FAQs 

How do you treat armpit rash? 

Start by stopping any product that might be causing irritation. Keep the area clean and dry, wear loose clothing, and apply a mild hydrocortisone or antifungal cream if needed. If the rash doesn’t improve or becomes painful, see a healthcare professional for diagnosis and treatment. 

What does a fungal underarm rash look like? 

A fungal rash under the arms often appears as shiny, slightly moist patches with clearly defined edges. On lighter skin, it may look red or pink, while on darker skin, it can look dark brown, purple, or gray. You might notice small bumps or spots just outside the main patch, and the area can feel itchy or irritated—especially in warm, sweaty conditions. 

What does a deodorant armpit rash look like? 

A deodorant-related rash can make the skin under your arms feel dry, itchy, or irritated where the product was applied. On lighter skin, it may appear red or pink, while on darker skin, it can look darker brown, purple, or gray. You might notice small bumps, flaking, or even blisters if the irritation is severe. If the rash doesn’t clear up after switching products, or it becomes painful or swollen, it’s best to see a healthcare professional for proper diagnosis and care. 

If you’re still asking, “Why are my armpits red and itchy even after trying all this?”, it may be time to check in with a doctor. Persistent rashes could signal something more serious, like an ongoing armpit fungal rash or another skin condition. 

At the end of the day, armpit rashes are common and while they’re annoying, they’re usually treatable. With the right care, a few lifestyle tweaks, and the right deodorant, you can keep your underarms feeling calm, fresh, and rash-free. 

References 

1. Cleaveland Clinic. What is Candidiasis? 2025

2. Health Central. Armpit Rash? How to Know if it’s Eczema. 2025

3. Psoriasis. Inverse Psoriasis. 2025.

4. Cleaveland Clinic. Colloidal Oatmeal. 2025.