What are the common causes of hair loss in dogs?

Common causes include external parasites, skin infections, allergic reactions, and hormonal changes; diet and environmental factors may also play a role. A vet should evaluate the history and run appropriate tests to confirm the cause.

What initial home care can I provide?

At home, avoid harsh shampoos, keep the affected area clean, document the progression with photos, and bring your dog to the vet promptly if lesions appear or the condition worsens.

What tests does the vet usually run to find the cause?

The vet will typically perform a physical examination, skin scraping, cytology, and cultures; a skin biopsy or further imaging may be arranged if needed to clarify the diagnosis.

How long does it take for hair loss to improve?

Recovery time depends on the underlying cause. Parasitic or infectious causes often improve within a few weeks of treatment; chronic or hormonal conditions may require longer monitoring. Follow your vet's recommended schedule for check-ups.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

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Disease Guide

Canine Alopecia (Hair Loss in Dogs): Symptoms, Diagnosis & Home Care [2025]

Dog hair loss has many causes, including infections, allergies, and hormonal disorders — a vet examination is needed to identify the underlying cause.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap editorial team

Sources: WSAVA, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•The wound continues to bleed heavily and the bleeding cannot be stopped
•Large areas of skin across the body are damaged with heavy discharge
•Extreme lethargy, slow responses, and unwillingness to move

Schedule a veterinary visit soon (within 24-72 hours)

•Localized skin remains red, swollen, or broken
•Frequent scratching or chewing continues for more than several days
•Dandruff, odor, or pigment changes remain clearly noticeable

01What Symptoms Indicate a Problem?

Canine hair loss typically presents as patchy or generalised thinning, accompanied by skin changes. Watch for scratching, dandruff, or unusual odour to help assess the situation.

Patchy or generalised thinning and shedding of fur
Skin redness, hyperpigmentation, or crusting
Frequent scratching, biting, or rubbing of specific areas
Visible dandruff, greasy coat, or increased skin odour
If hair loss persists or is accompanied by skin lesions, a specialist evaluation is recommended

02How to Assess the Problem at Home: Key Observations and When to Seek Emergency Care

Keeping systematic records and photos at home helps your vet understand the progression and possible triggers.

Take clear photos of the affected areas and note the timing and progression
Record the frequency, timing, and triggers of scratching or biting
Check the skin for redness, discharge, open wounds, or crusting
Monitor for changes in alertness, appetite, or water intake
Watch for changes in elimination habits or a decrease in daily activity
Seek veterinary care promptly if symptoms worsen or skin lesions increase

03How Will the Vet Diagnose the Condition? Common Diagnostic Tests

Your vet will combine a detailed history with multiple tests to identify the cause of hair loss and decide whether further workup or specialist referral is needed.

Thorough physical examination

assessing the pattern of hair loss and associated skin changes

Skin scraping or microscopy

looking for evidence of parasites or fungal infection

Cytology

identifying purulent discharge or inflammatory cells

Skin biopsy (if indicated)

confirming chronic or unusual lesions

Bacterial or fungal culture

guiding the most appropriate treatment

Advanced imaging (e.g. CT) or specialist referral when necessary

04Treatment and Care After Diagnosis: Medications, Dietary Adjustments & Home Care Guide

Treatment is tailored to the test results; consistent home care and regular follow-up appointments improve outcomes and reduce the risk of recurrence.

Follow the targeted treatment plan based on test results and monitor the response
During medication, observe for side effects and therapeutic progress as directed by your vet
Dietary modifications or environmental allergen management may be beneficial
Keeping the area clean and appropriately moisturised reduces secondary irritation and infection
Schedule regular follow-up visits to assess skin recovery and any further testing
Return to the vet promptly for reassessment if there is no improvement or symptoms worsen

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Find the Cause Quickly

Bring clear photos and short videos of the affected areas (including full-body and close-up shots)

Note the onset, progression, and any home treatments you have already tried

List the frequency of scratching, when it occurs, and any possible triggers

Describe any recent changes in diet, boarding, bathing, or environment

Bring previous diagnostic reports, culture results, or a list of current medications

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

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