Can PRP injection in the scalp trigger hidden allergies?

Hi, and thank you for your question regarding PRP. PRP consists of plasma drawn from your own blood, therefore it’s highly unlikely that your allergic reaction was caused by the PRP itself. However, several other components of your PRP procedure could have produced an allergic reaction, such as any pain-reducing agents if used.  You may also have had a reaction to any of the items used during the procedure such as latex. Schedule a follow-up with your board-certified facial plastic surgeon or a dermatologist in order to better diagnose your allergic reactions. Good luck with your PRP treatments! I wish you good health.

It's unlikely pure PRP (which comes from your body) would create allergic reactions. However, several medications are injected at the time of the procedure which certainly could have caused a delayed reaction. Speak with your injector. Best of luck, Dr. ALDO 

In my  opinion, if you were injected with pure PRP without any additives, there should be no allergic reaction. If diagnostic tubes were used a reaction is entirely possible. If an extracellular Matrix was used or if the PRP was activated, it is possible to have an allergic reaction. If lidocaine was added to the mixture, this could be another source of reaction.PRP hair MD.com