What is desensitization?

What is desensitization?
Desensitization is a process where the patient is given a small quantity of an allergen and the amount is slowly increased. This tricks the immune system into accepting a medication to which it would normally overreact to.

Antibiotic desensitizations
Let's say you are allergic to meropenem. The desensitization would start with 1/10,000 of a typical dose. We would roughly double the dose at 15 minute intervals. Throughout this process you and the team will monitor for any reactions (ie rash or itching). If you've had no reactions then you've tolerated the desensitization and now you can recieve normal doses safely.

The desensitization only lasts as long as you continue to receive the antibiotic on a regular schedule. If several doses of an antibiotic are missed or if you've finished treatment with that antibiotic then your immune system becomes resensitized and you could be at risk for allergic reaction the next time you receive the antibiotic. That's why if you need to be treated with this antiobiotic again in the future, you would have to undergo the desensitization process again.

Based on a study that looked at 95 desensitizations at St. Michael's in 10 years, 87 were successfully completed. The most common symptoms were itchiness and rash and no patients had anaphylactic reactions.