My left breast has been red underneath aand swollen and is hard to the touch since this morning and I have looked online but still can't find out what it is or what is causing it

That is why you go see a dermatologist. Not a good idea to ask for diagnosis and treatment on line as the answers you receive may be wrong.

I am assuming you keep everything clean and dry? Wash your bras and air out your breasts?

I walk around quite often braless, holding up my breasts to air them out. Doesn't everyone do that??

Sounds like a rash from perspiration under the breasts, solved with some ointment similar to diaper rash ointment, anything with fish oil in it. Most of all, dry well underneath after a shower or bath.

There are various skin conditions you can get under the breasts (and armpits, groin, belly button, etc). One is called intertrigo. It is usually yeast but can also be bacterial. It produces a beet red or even purple rash, and a smell much worse than the usual one.

Well, not thinking of the rash that has an odour, but is very red and sore, and is bacterial. Many women get this in the summer from sweating.

@tickle. It is a matter of wearing something that wicks the moisture away. It is probably a sweat rash. Depending on the size of her breasts the underside wouldn't dry out right and could cause the rash. It isn't really comfortable to have a layer of fabric, like a tank top or what not, between your breast and your chest but it can be required to make sure the skin has a chance to breath. Some of the bras I have seen, do not wick moisture away as well as they could.

@Craven, yes, I think that is what I said. Personal Support Workers are involved in rashes like this all the time; advising and treating and curing.

It was hard to tell if you were being sarcastic and condescending or agreeing.

That is upsetting ! You thought I was being sarcastic or condescending? I don't think I would be either to another member in this community. Thanks for the vote of confidence, but I was agreeing because we were supposedly in the same page.

I completely misread that. I am so sorry. :-( I have had baby brain something fierce over the last couple days. It has been a mixture of exhaustion and an illness coming on.