PPD Allergy (para-phenylenediamine)?!

I dyed my boyfriends hair and he broke out in a TERRIBLE rash and it kept getting worse. We found out he was allergic to a chemical called PPD (para-phenylenediamine). He went to the doctor and they gave him steroids and antibiotics. We thought it was getting better but then got even worse. Its been like this for 2 weeks now and he has finished his perscription. He is going back to the doctor in a couple days but he is having a terrible time trying to keep it from itching and "leaking" (gross). Does anyone know anything that might help? Benadryl doesnt do much.