

Unknown rash- any help or suggestions is appreciated!
Looking for suggestions on a rash i have. It’s currently being treated as an allergic reaction. Currently on steroid that did almost immediately clear it but it started reappearing yesterday after i started the lower dose of the steroid to start weening off of it. Papule are “sterile” and not caused by bacteria or fungus. Had an allergy test and wasn’t found to have any new allergies besides the usual seasonal/ dust allergies. I have also tried cutting out normal food allergies but rash would still appear. tends to show up when I’m stressed. My dermatologist is at a loss and is talking to her medical group but currently don’t have any idea as to what is causing it besides stress. Shows up as little bumps and then turns into whiteheads. Biopsy showed general inflammation but nothing else like mast cell activation. It is not acne, and only responds so far to anti inflammatory medication like sulfur topicals and oral steroids. Topical steroids did not help, and antibiotics is what initially created this consistent flare. Any ideas or suggestions would be appreciated. It started appearing about 5 years ago. I am 27. This is the longest I’ve had it consistently show up. I am an overall healthy person with no underlying health conditions. It only appears from my waist up. Occasionally on my arms but mainly my torso and face. Thanks!
Personally i tend to think it is something like mast cell activation syndrome as it comes and goes along with severity depending on my stress levels, but my dermatologist said the biopsy didn’t show any mast cells.