Why Is My Dog Losing Hair?

Common Questions You May Be Asking

Hair loss (also known as alopecia) is a common reason dogs are referred for dermatology assessment and is often associated with allergies, infection, parasites or hormonal conditions affecting the skin and coat.

If your dog is losing hair or showing changes in their coat, you may be asking:

• Can infections or parasites cause hair loss?
• Why is my dog losing hair in certain areas?
• Why is my dog shedding more than usual?
• When should I be concerned about hair loss?

These are some of the most common concerns we see, and they are often linked to the same underlying causes.

What Causes Hair Loss in Dogs?

Hair loss is a symptom, not a diagnosis. Identifying the underlying cause is key to effective treatment and coat regrowth.

The most common causes include:

• Allergic skin disease (dog allergies) → Learn more
  Allergies can lead to inflammation, itching and self-trauma, which may result in hair loss or thinning of the coat. These can include things like environmental allergy (canine atopic dermatitis), food reactions and flea allergy.
• Skin infections → Learn more
  Bacterial or yeast infections may cause patchy hair loss, coat change, redness or irritation.
• Parasites → Learn more
  Mites and other parasites can cause hair loss, sometimes without obvious itching in early stages.
• Hormonal (endocrine) conditions → Learn more
  Conditions such as hypothyroidism or other hormonal imbalances can lead to more symmetrical or generalised hair loss.
• Less common or more complex causes
  Less commonly, hair loss may be associated with immune-mediated disease, genetic conditions or other dermatological disorders.

In many dogs, more than one contributing factor may be involved, particularly where signs are ongoing or recurrent.

What Does Hair Loss Look Like?

Hair loss does not always appear the same in every dog. Signs can include:

• Bald patches or areas of alopecia
• Thinning of the coat or reduced coat density
• Patchy or uneven hair loss
• Broken or damaged hairs
• Red, inflamed or irritated skin
• Changes in coat quality or texture

Some dogs lose hair in specific areas, while others show more generalised coat change. The pattern and distribution of hair loss can provide important clues to the underlying cause.

Why Does It Keep Coming Back?

In many cases, hair loss becomes a recurring issue because the underlying cause has not yet been fully identified or controlled. Conditions such as allergies, infection or parasites can lead to repeated inflammation, self-trauma or disruption of the hair cycle.

This may result in:

• Recurrent or cyclical hair loss
• Periods of regrowth followed by further coat loss
• Only partial or temporary improvement with treatment

Without addressing the primary cause, hair loss often persists or recurs over time.

When Should You Seek Help?

If your dog is showing these signs, the first step is to consult your primary care veterinarian, who can assess your dog and begin initial treatment.

Further investigation or referral may be recommended if your dog:

• Has persistent or worsening hair loss
• Has bald patches, thinning coat or coat changes
• Has associated redness, irritation or infection
• Is not improving with routine or first-line treatment
• Has recurrent or unexplained coat loss

In these cases, specialist dermatology assessment starting with a dermatology consultation can help identify the underlying cause and guide more effective, long-term management. 

Early assessment can help prevent progression and reduce long-term discomfort.

Frequently Asked Questions