I am not sure if you ever check this thread anymore as it's so old but I developed a salicylic allergy after years of using it. (It was actually that same product - Paula's choice bha 2% that I used to use.) It was a great product for my skin but slowly I became itchy after using it and eventually my face started to swell. I used it intermittedly so it took me a long time to pinpoint the cause but that was it. Also, aloe contains salicylic acid and that will cause my face to swell.