After I checked on this sight and others I think you are right. Why do they keep bleeding when scratched. I have had this one for 15 or more years but it is getting really hard , not sore and thought I should get some ideal what it was. When I talk to my doctor she said it wasn't anything but didn't say what it was. After it bled and bled I went in and she said it wasn't anything to worry about. But people are noticing it more and more. "thanks again
Hello,
The symptoms are suggestive of sebaceous cyst. A sebaceous cyst is a closed sac occurring just under the skin which contains a "pasty" or "cheesy" looking substance called keratin. They may occur anywhere on body but scalp, ears, back, face, and upper arm, are common sites for sebaceous cysts. Blocked sebaceous glands, swollen hair follicles and excessive testosterone production will cause such cysts.
Generally no treatment is required but they become painful then it means they are infected, then surgical excision by traditional wide excision, minimal excision, and punch biopsy excision may be required. It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.