What causes painful red lump which occurs on the body?
Patient: I'm a healthy 28 year old male with no history of any lump issues.  For slightly over a month now I've had a red lump under my arm.  That alone isn't the alarming thing.  What is getting to me is that it seems to drift around.  It will be a raised red lump one day, then seem deflated, then gone.  A few days later, it will have shifted locations and be raised again.  it's not very large, about the diameter of a pencil eraser and raise only about the height of a regular small zit.  But it does hurt, and it seems to leave a trail when it moves not unlike a stretch mark. I'm really concerned, and have not seen a dermatologist. Doctor: Hi.Thanks for your query.Well, this looks to be hidradenitis, a condition of the skin of the armpit. One gets the exact symptoms you have. Take a course of an antibiotic. Long-term doxycyclin helps a lot. You need to clean the area with Povidone iodine 4 times a day.IT is most likely to get healed up with this. Occasional patient needs Surgery to excise the affected skin area. You may not need it.