Is it possible to build up an allergy to PPD? Granted I have had approx 12 TB skin tests since 2000 and will get one every year for the rest of my life; is it possible to develop and allergy to PPD? This is the second time I have gotten a red raised area just under the size of a quarter the evening after getting a TB test. It looks exactly the same as last time and last time it was gone the next day and stayed gone. It has happened again but this time I have a runny nose; which could just be coincidence. I took a picture of it but I did not know if I could post it; I am not asking for medical advise...I am just curious.