Loss of Smell in Older Dogs: Signs, Causes, and Care

Scent is not a secondary sense for dogs—it is the primary channel for gathering information about their environment. A dog on a walk reads the ground with its nose the way we scan a room with our eyes. When olfactory ability fades, the dog loses a fundamental source of environmental awareness, which can reduce appetite, increase anxiety, and diminish interest in activities it once enjoyed.

Research supports that age-associated olfactory decline occurs in dogs. The specialized olfactory epithelial cells lining the nasal passages decrease in number over time, and the efficiency of olfactory nerve transmission slows. This process is typically gradual, bilateral, and symmetrical—progressing slowly enough that the dog adapts incrementally.

Quantifying exactly when or how much smell declines is difficult. Dogs cannot report their experience, and formal olfactory testing is not routinely performed in clinical practice. Observable changes—particularly around food interest and environmental exploration—are the most reliable indirect indicators available to owners.

If smell loss appears sudden, dramatic, or affects only one side of the nose, that pattern suggests a medical cause rather than age-related change.

Because dogs cannot tell you their nose is not working as well, watch for these behavioral clues:

• Decreased interest in food, especially foods the dog previously enjoyed.
• Failure to notice treats placed nearby unless the dog sees them.
• Reduced interest in sniffing during walks.
• Not responding to the smell of food being prepared in another room.
• Increased reliance on vision or hearing to locate objects.
• Less interest in scent-marking behaviors.

These signs overlap with other conditions—pain, nausea, cognitive dysfunction, dental disease, and depression can all reduce appetite and engagement. They are best evaluated as part of a complete veterinary assessment rather than attributed solely to smell loss.

Several conditions beyond normal aging can impair olfactory function and require specific treatment:

• Nasal infections. Bacterial, fungal (such as aspergillosis), or viral infections can inflame or damage the nasal lining.
• Dental disease. Severe dental infections—especially of the upper premolars and molars—can extend into the nasal passages and interfere with scent detection.
• Nasal tumors. Growths within the nasal cavity can obstruct airflow and destroy olfactory tissue. Nasal tumors are more common in older dogs.
• Nasal polyps or foreign bodies. Physical obstructions block scent molecules from reaching the olfactory receptors.
• Chronic rhinitis. Persistent nasal inflammation from allergies or environmental irritants can gradually damage the olfactory epithelium.
• Neurological conditions. Brain tumors, head trauma, or neurodegenerative diseases can affect the olfactory nerves or the brain regions that process scent.
• Medications. Some drugs may affect olfactory sensitivity. If smell changes coincide with a new medication, mention the timing to your veterinarian.

Because some of these causes are treatable—and some are serious—any noticeable change in a senior dog's sense of smell warrants evaluation.

Seek veterinary attention promptly if you notice:

• Sudden onset — smell loss or appetite change developing over days rather than months.
• One-sided nasal discharge — may suggest infection, a foreign body, or a nasal tumor.
• Bloody nasal discharge or frequent nosebleeds — never normal and should not be dismissed.
• Facial swelling or visible deformity around the nose or muzzle.
• Breathing difficulty — noisy breathing, snoring, or labored airflow that is new or worsening.
• Significant weight loss associated with reduced food intake.
• Pain — pawing at the face, reluctance to eat hard food, or head shaking.

Your veterinarian may recommend a nasal examination, imaging (radiographs, CT, or MRI), dental evaluation, or blood work depending on the clinical picture.

For dogs whose reduced smell is age-related—after medical causes have been addressed or ruled out—these strategies can help maintain appetite and engagement:

• Warm food gently (to just below body temperature) to release more aroma. Avoid overheating, which can burn the mouth.
• Use wet food or add warm water to kibble to enhance scent.
• Offer food in a quiet, consistent location to reduce mealtime stress and let the dog focus on eating.
• Maintain dental health — oral pain compounds appetite problems regardless of smell.
• Track weight and intake — a simple log helps you and your veterinarian spot gradual decline before it becomes severe.
• Adapt enrichment activities — scent games can still work with stronger-smelling items. If sniffing becomes less rewarding, shift toward texture-based or movement-based enrichment.

Avoid adding salty or fatty broth or supplements that could unbalance your dog's diet without veterinary guidance. Any sustained change in diet composition should be discussed with your veterinarian.

While age-related olfactory decline cannot be reversed, understanding and accommodating it helps your senior dog maintain comfort and quality of life.

This article is for educational purposes only and does not replace professional veterinary advice. If you notice changes in your dog's sense of smell, consult a veterinarian.

Sources:

1. Age-related changes in the olfactory system of dogs
2. When the Nose Doesn’t Know: Canine Olfactory Function
3. Loss of Sight, Hearing, or Smell in Senior Pets — Lap of Love

Related articles: Sensory Changes in Senior Dogs · How to Stimulate Appetite in Senior Dogs · Senior Dog Not Eating · Dental Disease in Senior Dogs