Hair loss in an old dog can be worrying, especially when it seems excessive or appears suddenly.
Some shedding is normal, but noticeable thinning, bald patches, or changes in coat quality often point to underlying health or skin issues.
Old Dog Hair Falling Out: Why It Happens
Hair falling out in an old dog is usually caused by aging changes, skin conditions, hormonal imbalances, or underlying health problems.
When dogs age, their skin becomes thinner and less resilient, and their hair growth cycle slows down, while issues like allergies, infections, or endocrine disorders can further disrupt normal hair growth.
In many cases, hair loss is not just cosmetic—it’s a sign that something deeper needs attention.
Old Dog Hair Falling Out: Symptoms
If your old dog has hair falling out, you may notice:
Increased shedding or loose hair
Bald spots or patchy hair loss
Thinning coat over time
Dry, flaky, or irritated skin
Redness or inflammation
Itching, licking, or scratching
Changes in coat texture (dull or brittle)
Scabs or sores in affected areas
Read more: Old Dog Dull Coat (Why coat quality changes with age)
Old Dog Hair Falling Out: Common Causes
Natural Aging and Coat Changes
As dogs age, their hair growth cycle slows down and becomes less efficient. Hair may take longer to regrow, and follicles may produce thinner, weaker strands.
This can lead to gradual thinning across the body rather than dramatic bald spots. The coat may also lose its density and softness, making hair loss more noticeable.
While mild thinning is normal, significant or uneven hair loss usually points to another issue.
Hormonal Imbalances
Hormonal disorders are a major cause of hair loss in older dogs. Conditions like hypothyroidism slow down metabolism and affect hair growth, often leading to symmetrical hair loss along the body.
Cushing’s disease, on the other hand, can cause thinning skin and patchy hair loss due to excess cortisol levels.
These conditions often develop gradually and may also include symptoms like weight changes, lethargy, or skin abnormalities.
Allergies
Allergies can cause skin irritation, leading to scratching, licking, and hair loss. Older dogs can develop new sensitivities even if they’ve never had issues before.
Environmental allergens like pollen or dust, as well as certain foods, can trigger inflammation in the skin. This repeated irritation damages hair follicles and causes shedding or bald patches.
Hair loss from allergies is often accompanied by redness, itching, and discomfort.
Parasites
External parasites can cause intense itching and irritation, leading to hair loss.
Flea infestations are a common culprit, especially in dogs with flea allergy dermatitis, where even a single bite can trigger severe reactions.
Mites can cause conditions like mange, resulting in patchy hair loss, scaly skin, and inflammation. Older dogs may be more vulnerable due to weaker immune systems.
Skin Infections
Infections can damage the skin and hair follicles, leading to localized or widespread hair loss.
Bacterial infections often develop secondary to other issues like allergies or wounds, while fungal infections can cause circular bald patches.
These conditions are usually accompanied by redness, odor, or discharge and require treatment to resolve.
Nutritional Deficiencies
A lack of essential nutrients—especially protein, fatty acids, and vitamins—can affect coat health.
Older dogs may have difficulty absorbing nutrients efficiently, even if they are eating regularly. This can lead to a dull coat and increased hair loss.
Over time, poor nutrition weakens the hair structure and slows regrowth.
Illness
Systemic health problems such as kidney disease, liver issues, or immune disorders can impact the skin and coat.
When the body is under stress or not functioning properly, it may prioritize vital organs over hair growth, leading to shedding or thinning.
Hair loss in these cases is often accompanied by other symptoms like lethargy, weight loss, or appetite changes.
Read more: Old Dog Itching and Scratching (What’s causing the irritation)
Old Dog Hair Falling Out: What to Do
If your old dog has hair falling out, start by observing the pattern and severity. Gradual thinning may be age-related, while sudden or patchy loss often signals a problem.
Maintain a balanced, high-quality diet that supports skin and coat health. Adding vet-approved supplements like omega fatty acids may help improve coat condition.
Regular grooming can help remove loose hair, stimulate the skin, and distribute natural oils.
Keep your dog’s environment clean and monitor for signs of parasites or allergens that could trigger irritation.
If your dog is scratching excessively or showing discomfort, it’s important to address the cause rather than just the symptom.
When to Call or Visit Your Vet
If your old dog’s hair loss is sudden, severe, or patchy, it’s best to consult your veterinarian.
Signs like redness, sores, or infection should be evaluated promptly.
If hair loss is accompanied by weight changes, lethargy, or changes in appetite, an underlying health condition may be present.
Persistent itching or discomfort is another reason to seek veterinary care.
If the condition does not improve with basic care, a professional diagnosis is needed.
Old Dog Hair Falling Out: Treatment
Treatment for hair loss in an old dog depends on the underlying cause.
Your vet may perform skin tests, blood work, or allergy testing to determine the reason for hair loss.
Hormonal conditions are typically managed with medication, while infections require antibiotics or antifungal treatments.
Parasites are treated with appropriate preventive or medicated products.
Nutritional adjustments or supplements may also be recommended to support skin and coat health.
Key Takeaway
Hair falling out in an old dog is common, but it shouldn’t be dismissed as just aging—especially if it’s excessive or uneven.
By identifying the cause, providing proper care, and seeking veterinary advice when needed, you can help restore your dog’s coat and comfort.
Early attention can make a big difference in keeping your dog healthy and happy in their senior years.