Unlike thinning hair or hair loss in humans, these are not typical aging signs in senior pets. Most often, alopecia (i.e., hair loss) in dogs and cats is caused by an underlying condition requiring veterinary care.
Alopecia presentation in senior pets
Senior pet alopecia can vary greatly in presentation—progression can be sudden, seemingly appear overnight, or slow. Hair loss may be widespread (i.e., diffuse) or limited to a single body part. Pets may appear unbothered by their hair loss, or groom and scratch excessively. Hair loss lesions may be crusty and inflamed or look like normal skin. 
Regardless, your senior pet needs prompt veterinary care whenever you first see a change in their coat, or their behavior. Early diagnosis and treatment will improve your pet’s outcome and prevent additional complications. We present five reasons why your senior pet may be losing their hair.
1. Allergies in senior pets
Rather than sneezing and coughing, dogs and cats often react to allergies with skin and ear problems. While your pet may seem too old for allergies, they can occur at any time, triggered by environment or parasites. They can have allergic reactions to materials (e.g., bedding, toys, bowls, and litter), food ingredients (e.g., proteins such as chicken, beef, pork, eggs, dairy, and wheat gluten), or unavoidable indoor and outdoor irritants (e.g., pollen, grasses, dust/storage mites, and mold). If you think of allergies as something one is not born with but something that develops over time, it makes sense to rule out allergies in older pets.
Allergies may be seasonal or ongoing, depending on their cause. They typically are incredibly irritating to pets.
2. Infection or parasite infestation in senior pets
Bacterial skin infections, which are often accompanied by scaling, crusting, discharge, or redness, can cause pets irritation and hair loss. In senior pets, skin infections are often secondary to husbandry issues, such as:
- Matted hair coat — Senior pets’ hair coats may become matted, because they no longer self-groom or visit the groomer frequently. Matted hair traps moisture and dirt against the skin, and prevents proper airflow, creating a bacterial breeding ground.
- Urinary or fecal incontinence — Prolonged skin contact with urine or fecal matter breaks down the skin barrier.
- Pressure sores — Senior pets may spend long hours resting in the same position, putting pressure on bony points, such as elbows, hips, and hocks (i.e., ankles). Over time, repeated, prolonged pressure—especially on hard surfaces—causes hair loss, callus formation, and ulceration.
If senior pets are not kept on a year-round flea, tick, and heartworm prevention protocol, parasites may be to blame for hair loss. Flea allergy dermatitis (FAD) is a hypersensitivity reaction to flea saliva, and a single bite can cause rapid, intense signs, including hair loss over the base of the tail and the tail itself.
3. Nervous or obsessive grooming in senior pets
Age-related changes, such as hearing or vision loss, or cognitive dysfunction syndrome (i.e., dementia), are often accompanied by increased anxiety and nervous behavior. Anxious cats and dogs may self-soothe with repetitive behavior like overgrooming that leads to hair loss (i.e., psychogenic alopecia). Self-grooming (e.g., licking, chewing, and scratching) may include hair pulling, chewing, or loss because of skin irritation and secondary infection. Common overgrooming sites have the feet, limbs, flank, and abdomen. It is best to assume your pet has a reason for overgrooming because dementia and anxiety are common problems in older pets
4. Endocrine or immune-related disorders in senior pets
Conditions such as hypothyroidism (i.e., low thyroid) in dogs, diabetes mellitus, and Cushing’s disease (i.e., overactive adrenal gland) are common reasons for senior pets’ hair loss. Pets can also develop Cushing’s disease after prolonged steroid use. These conditions typically cause symmetrical rather than patchy hair loss.
5. Pain in senior pets
Pets will also overgroom because of pain. Unfortunately, this is all too common. They may lick or chew in specific locations where they are experiencing discomfort, such as over an arthritic joint like a knee or front leg. Pets lick and chew to eliminate the pain and may experience endorphin release that naturally occurs during grooming. Think about what you do when you have pain somewhere – you often rub it. Pets do the same thing by licking the painful area. Untreated overgrooming cases can lead to skin infections, ulceration, and hot spots. Just importantly, when overgrooming is untreated, arthritic pain is untreated. To resolve these issues, both the skin and the underlying pain must be addressed. Never assume your older dog or cat does not have pain because oftentimes they do.
If you notice that your senior pet’s hair is thinning, falling out, or looking patchy or bald, schedule an appointment with your veterinarian, who will likely check your pet for parasites, examine for arthritic pain, ask about signs of dementia, and/or recommend diagnostic skin tests for hormonal imbalance. Hair loss treatment in senior pets depends on the cause most issues can be well managed or resolved.
If you are interested in discussing Hospice care for your senior pet, please call our office at (802)871-2329 to schedule a telemedicine.