There's a reason dogs are used for sniffing out smells; your pup's nose is part of a highly developed system, making his sense of smell extremely powerful. Pal's superior snout makes him useful to law enforcement and search and rescue in the search for people, firearms, explosives and drugs.
Dogs are prone to aging, just like people. As they age, their sense of smell can deteriorate, just as eyesight and hearing can begin to fail. If you've noticed Pal's appetite isn't what it used to be, it could be that he isn't picking up the delectable aroma of his favorite dog food. Try lightly warming his favorite canned food to make it more aromatic.
Sinusitis and Rhinitis
Old age isn't the only reason Pal can have a hard time picking up scents. Sometimes his smelling equipment can be affected, impairing his sniffing ability. If his nose is inflamed, Pal's suffering from rhinitis. If his nasal passage is inflamed, he has sinusitis. If he has either condition, chances are he's not smelling much of anything.
Causes of Sinusitis and Rhinitis
If Pal has sinusitis or rhinitis, chances are it's from a viral infection, although pollen, dust, mold and smoke can trigger either condition. In older dogs, it's not uncommon for tumors or infected teeth to be culprits of either condition. Symptoms of rhinitis and sinusitis include sneezing, snoring, nasal discharge and difficulty breathing. If Pal paws at his face, it may indicate a foreign object is in his nose, causing his problems. Since he's not able to smell very well, his appetite will likely be affected.
If you suspect something's amiss with Pal's sniffer, the vet can determine whether he has a medical condition, such as sinusitis, or if he's experiencing age-related loss of smell. The vet will consider Pal's medical history, conduct a physical exam and may order blood work and x-rays if his nose or nasal passage is inflamed. If Pal has sinusitis or rhinitis treatment will depend on the cause. If the problem is a bacterial infection, antibiotics will help clear up the infection. If Pal's loss of smell is a natural by-product of his senior status, talk to the vet about using vitamin A. Whole Dog Journal notes that the vitamin helps stimulate odorant molecules, though there aren't studies to confirm benefits or dosages for dogs.