Joey, an Alsatian-Collie cross, had been constantly breaking out in a rash.
His owner, Scott Muirhead, from Hamilton, South Lanarkshire, took him to vets at Taylors Practice in Glasgow who diagnosed numerous allergies.
Since the poorly pooch began his new medication his condition has vastly improved.
Mr. Muirhead, 36, told the BBC Scotland news website: "We've spent the past year trying to figure out what was wrong with him.
"His skin was terrible. He was breaking out in boils and scratching all the time.
"We have been trying special diets but really weren't getting anywhere."
Vets at Taylors eventually carried out blood tests on Joey and were astonished by the results.
"He was basically allergic to everything," said Mr. Muirhead.
"We were given a list and it included all types of meat, dairy produces, long grass, daisies, dandelions, cat hair and other dog hair."
Scott Muirhead, and his partner Lisa McCormack, 25, have had Joey, who turns five next week, since he was a puppy and were baffled by the fact that up until last year he had never had any problems with his diet.
"We used to feed him everything and anything but now Joey can't have any treats, "said Mr. Muirhead.
"We were told he could only eat things like potatoes, porridge and barley."
The couple hopes a new medication they are trying Joey on might give him a new lease of life.
Mr Muirhead added: "His hair is starting to grow back and his skin seems to be in better condition. "It is still early to tell but he seems to be picking up and it does seem to be making a difference."