Zocdoc Answers

Medical questions & health advice by board certified doctors

"What causes blood cysts to form on the breasts?"


I've been developing cysts on the underside of my breasts, and it seems like they're just filled with blood. Does this indicate a serious problem? I've been thinking it might just be an allergic reaction to my bra, but now I think the problem is getting worse. Should I see a doctor?


Anytime patients develop any new growth especially in the area of the breast, it can be a source of anxiety for patients. In the case of cysts, they can be a benign but annoying problem, or they can indicate a serious problem. That is why you should see a physician soon.

See a doctor who can help

Find a Primary care-doctors near you

Cysts in general are membrane lined structures that can be filled with fluid, air, blood, or some other bodily substance. Blood cysts can be caused by trauma to an area of the skin which results in small blood vessel breaks which allow the hollow membrane-lined capsule to fill with blood. In this case, it is possible that trauma from a very tight fitting bra could result in very small blood cysts. Only your doctor will be able to tell for sure. I suggest you see a doctor about this issue sooner than later. Your symptoms have the potential to be something that needs fixing. You can start by scheduling an appointment with your primary care physician who can help determine whether or not these cysts are dangerous, whether they can be treated, or if they need to be looked at by a specialist. Good luck.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.