I give him shots about once a month. But they don't last. He sounds like he could choke on his mucus. He is a boxer 64lbs about 7 ish A rescue dog, so not sure about the age.

Is he on any oral antihistamines? If not, maybe those would benefit him along with the allergy shots.

There are also allergy drops that you can purchase through your vet. Samples are taken from the dog and a serum is created that is suppose to help relieve the allergy issues. Its by Heska. Heska - ALLERCEPT® – Allergy Testing and Treatment Program: canine, feline, and equine serum IgE testing and immunotherapy for cats and dogs..