My wife also has allergic reactions to Carbo (and Oxaliplatin) and a number of other drugs. In order to maintain treatment she takes very high doses of steroids the night before and then immediately before treatment and she also has IV piriton (anti hysthamine). She needs to take lorazapam to counter the more aggressive aspects of steroid but it is meaning that she is tolerating her treatment.
She has her treatment (Oxaliplatin, 5FU & Avastin) all in one day, but it takes 8 hours.
This approach is pretty heavy handed and may not be to everyone's taste given the unpleasant effects of steroid (lack of sleep, aggression). It does have the benefit of dampening the chemo side effects for 24/36 hours after treatment though.
You say the platinum based drugs did well for you, so is there any way you can work with an allergist to help desensitize yourself to them? I, too, had an allergix reaction to carboplatin during my first recurrance and moved on to other drugs that did nothing for me. I switched doctors and medical facilities during that time, and have been told by my current doctor if the time comes to go back on IV chemo, he wants to try carboplatin again through desensitization. Many times, simply slowing down the infusion (so much that it could take 2 or 3 days to finish it) will make it possible to use it. Talk to your doctor about it and see if this might be an option for you.
Best wishes.
Gail