Let me first start out by saying that dermatologic conditions can be somewhat difficult to diagnose at times due to the fact that many different disease processes can manifest themselves similarly on the skin. What I mean by this is that what may look like acne
to the average person may be diagnosed as something completely different by a dermatologist
, which may explain why your condition is not responding to multiple different treatments (I don't mean any insult to your diagnostic abilities, but I am assuming that you aren't trained in dermatologic ailments). Now, even if it is acne, there are many different types, which can be caused by different things. For instance, there is something called Acne aestivalis which is a special form of a polymorphous light eruption that occurs typically in fair skinned people with exposure to UV rays. In this case avoiding UV light usually helps. Another form of acne called Acne mechanica is an eruption that develops after repetitive physical trauma to the skin. This could happen where a shirt sleeve repetitively rubs the arm. And the treatment may involve removal of the insult/trauma. Now of course the more common forms of acne involve obstruction of sebaceous "sweat" glands, and multiple factors could be involved including skin type, the soaps you use, detergents used to wash clothes, allergies, etc. I would suggest making an appointment with a Dermatologist to get to the bottom of it. I wish you all the best, and I hope that this was helpful.