What to Know if You Have a Rash Under Your Breast

What to Know if You Have a Rash Under Your Breast

The skin around your breasts is pretty sensitive, meaning a rash under your breast is almost an unavoidable affair.

Nothing itches quite like an underboob rash.

Itching under boobs is the height of inconvenience, so what gives?

New bra, sweat, infection, heat rash – a lot of things can cause irritation.

That’s why it’s always best to have a rash checked by a doctor so you can get the right treatment.

So let’s get you closer to narrowing down the culprit and getting back to living your breast life (sorry).

📝 In this article:

  • Why is my underboob red and irritated?
  • What does a rash under your breast mean?
  • What else can cause an underboob rash
  • What does a breast cancer rash look like?
  • How to get rid of rash under your breast

Why is my underboob red and irritated?

Why, why, why?

Honestly, it’s really easy to develop a rash under your boobs, especially if you have larger breasts or you’re nursing.

Even holding or wearing your small baby is enough to irritate the skin.

That being said, you’re more likely to get a rash if the skin gets wet and doesn’t have the chance to dry.

This can happen after a shower, swimming, sweating, or because of leaking breast milk.

Put simply: if air can’t get to your skin – or if there’s rubbing and chafing because of moisture – your skin gets weaker, and anything from sweat rash to a bacterial or fungal infection can take hold.

What does a rash under your breast mean?

No time for messing around, here’s some of the most common reasons for a rash under your breast so you can go back to sweet itch-free bliss:

Heat rash

Also known as prickly heat, this underboob rash is a common complaint in the summer.

And from baby-wearing mamas who don’t get a lot of personal space (we see you!).

Heat rash under boobs looks like small, raised, red spots which might blister or get itchy as they heal.

The best way to avoid this is to wash your skin after you’ve broken a sweat and wear loose-fitting, breathable clothing made from natural fibers like cotton, linen, or silk – this goes for your underwear too.

Allergic reaction

Changed your laundry detergent recently?

Had an occasion for a new strapless or stick-on bra?

What about a different moisturizer or even nipple butter?

If you’re allergic to a new product, it’s not unusual for the rash to show up under your boob because your bra sits so close to your skin.

This is also known as irritant contact dermatitis.

Depending on how severe your reaction is, your skin might be red and blotchy, or you might get raised hives.

Antihistamines can help with itching, but keep an eye out for the symptoms of a more severe allergic reaction.

Bra rash is no joke, but it’s a great reason to not wear one for a little while.


Speaking of reactions, it is possible to develop eczema under your breasts.

Yes, it’s more common to get eczema on your hands and face.

But anywhere your skin rubs together (think your elbows and the backs of your knees) is a beacon for eczema, and the skin under your boobs is no exception.

What makes eczema a little different from the standard underboob rash is that it’s chronic, usually very dry, and it can make your skin crack.

It tends to flare up and then calm down depending on things like your diet, the environment, or your stress levels.

Your doctor may even be able to prescribe you a steroid cream or gel to soothe the area and return your sanity.


Ah Mastitis – the bacterial infection most common among nursing mamas.

It happens when one of your milk ducts gets blocked.

You’re unlikely to get a spotty rash with mastitis, but your skin can become very red and hot.

You’ll probably also feel like part of your breast is hard and badly bruised, and you may get a high fever, chills, and fatigue.

Medically professionals reassure this usually resolves on its own, but there are steps you can take to find relief from the discomfort.

Often, this looks like taking painkillers, using a hot compress, and continuing to express milk.

Should symptoms not improve after 24 hours or worsen, go back to your doctor, who might prescribe antibiotics.

No suffering in silence here, mama.


Intertrigo is the most common fungal infection that affects the skin under the boobs.

It’s actually a form of candida (or yeast) infection – the main culprit for a smelly rash under the breast.

If intertrigo is your guy, your skin will probably be raw, inflamed, and very itchy.

A yeast rash under the breast can also crack or weep, and the discharge can smell bad.

It’s also pretty common for the same fungus to cause a thrush infection on your nipple in the early days of nursing, when your skin might be particularly tender and cracked.

If you think you have intertrigo, see your doctor so that you can get the proper cream or antifungal tablet to clear it up.

They’ll also rule out other conditions like scabies or psoriasis that would need a different treatment.


Shingles might not be the first thing you think of if you’re young and healthy, but if you had chickenpox as a child and you get rundown (like after another illness or after you’ve had a baby) it can happen.

Shingles is essentially the reactivation of chicken pox in a nerve root, and it’s not uncommon for the blistery rash to appear under one of your boobs.

Shingles rash usually appears on one side of the body, and you’ll probably also have a fever, chills, and nerve pain in your back and shoulders.

If you think you might have shingles under your breast, see your doctor straight away to collect some antivirals and zinc cream for the rash.

What else can cause an underboob rash

Still can’t put your finger on the itch? Here’s some other possibilities:

  • Psoriasis: Often triggered by hormonal changes or inflammation, this skin condition stems from increased production of skin cells resulting in scaly patches of skin. It’s the most common autoimmune rash.
  • Bacterial infection: Breast cellulitis is a common infection in women who have recently had breast surgery or radiation therapy.
  • Ringworm: A type of fungal infection that appears as round, red patches with a telltale ring. You may be familiar with its relative Athlete’s foot. Yes, it is equally as contagious, so be cautious and get treatment ASAP.

What does a breast cancer rash look like?

It’s not usually helpful to assume the worst, but since breast cancer is the most commonly diagnosed cancer in the US, everyone should know the signs and symptoms.

It can affect the skin, and a rash at the beginning of breast cancer is not uncommon.

So what does a cancerous rash look like?

  • Your skin might be dimpled: Called Peau d’orange, lots of people compare it to orange or lemon peel.
  • Your breast might look and feel inflamed: There’s a chance your skin might be red and warm to the touch.
  • Your skin might become flaky. Especially around your nipple (nipple ezcema).

If you notice any of these changes, it’s worth making an appointment to have your breasts checked, even if you can’t feel a lump when you do a self-exam.

How to get rid of rash under your breast

Unless it’s a problem you’ve had before, like a seasonal sweat rash or an eczema flare-up, it’s best to check with your doctor before you treat a rash by yourself.

It’s tempting to put something like a thick moisturizer on your skin when it’s irritated, but that won’t usually treat the underlying problem.

It might even stop the air from getting to your skin and make things worse.

So if the rash isn’t clearing up on its own, or if you have any other symptoms like pain or a fever, make an appointment.

From here, your doctor can prescribe you the right cream for what ails you, whether it’s an antifungal ointment, barrier cream, or a trusty antibiotic gel.

Until then, some helpful things you can do include:

  • Wash your skin regularly with plain, warm water, and pat it dry rather than rubbing it (no matter how tempting it is to scratch).
  • Go bra-free. Let your boobs breathe mama! 🌰🌰
  • Use unscented products in the area. Allergy-free soaps are best!
  • Wash your hands before touching your breasts or breastfeeding.

It’s never fun having an itch you can’t scratch, but you’re one step closer to some relief.

That being said, if it’s one time too many, better to enlist a professional who can give you more lasting ease.

Because hey, whether you’re deep in mama mode or not, taking extra care of your breasts is always breast, ahem, best practice.

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