Brief Answer:
Listed all possibilities, and have a request from you

Detailed Answer:
Hello ma'am and welcome.

Thank you for writing to us.

I have gone through your query with diligence and would like you to know that I am here to help. There are a few possibilities that can cause such a presentation, and I shall list how many ever come to my mind:

+Cellulitis: Is a bacterial skin infection that can affect one breast and thus cause swelling, but will appear with redness of the skin

+Mastitis: Is the inflammation of the breast which can be caused by various factors, clogging of ducts can be one of them

+Previous surgeries: Previous surgeries can result in formation of scar tissue, which expands and cause that breast to swell up

+Biopsies: If at all any biopsies were taken from the affected breast, then formation of scar tissue can take place in that breast

+Breast cyst

+Breast abscess

+Inflammatory breast cancer: Let me be honest, cancer cannot be ruled out; but presents with other symptoms like pain, redness, a dimple-like appearance of the breast, swelling, sometimes nipple discharge, inverted nipple, etc.

I would thus like to request you to attach clear images in the following views:

1. Frontal view with both breasts in the image

2. Lateral view

3. Close up of the affected breast (all possible views)

4. Image of the red rash below the nipple you mentioned

5. Close up of the nipple-areola complex

You can either attach all the clear images to our discussion here or email them to me at:

YYYY@YYYY

and please do not forget to mention 'ATTN: Dr. Shoaib Khan' in the subject line so that the email can be directed to me at the earliest.

I look forward to your response in order to help/guide you further. Please do not hesitate to write to me with any extra information you have.

Best wishes.

---