You could try one of these, instead of the Elizabethan collar: http://www.handicappedpets.com/acc/nobite/index.htm
Just FYI, according to a 2001 study, the most common food allergens in dogs are: beef, chicken, milk, eggs, corn, wheat, and soy. So, I might go with a grain-free fish-based diet, or an elimination diet first. For more information on ingredients in dog foods, you can visit "The Dog Food Project" online. Also, you may want to get your dog allergy tested - most dogs do not have food allergies, they suffer more from environmental or inhalant allergies. You can't hope to treat your dog successfully if you don't know the cause of the problem, and you could make the situation worse. If you can't afford care, consider Care Credit, or ask if your vet belongs to the American Animal Hospital Assn. They may be able to access a grant for you. There are several charities that help, too. imom.org; uan.org; and help-a-pet.org.
Regional Director for Massachusetts, International Positive Dog Training Association
Director, SeniorCare Pawsitive Connections Program
AKC CGC Evaluator #3669
Therapy Dogs, Inc. Tester/Observer
Sioux, CGC, TDInc.
Maska, CGC, TDInc.
Sequoyah, CGC
Fergie, Retired Lap Dog, Age 19
Dancer, CGC, TDInc. (1989-2006) #1 Heart Dog
"If you talk to the animals they will talk with you and you will know each other. If you do not talk to them you will not know them and what you do not know, you will fear. What one fears, one destroys." - Chief Dan George
"The fidelity of a dog is a precious gift demanding no less binding moral responsibilities than the friendship of a human being. The bond with a true dog is as lasting as the ties of this earth can ever be." ~ Konrad Lorenz