# Why Is My Dog Losing Hair?


## Key Takeaways

- Alopecia in dogs can stem from parasitic infestations (e.g., fleas, mites), leading to pruritus and secondary self-trauma.
- Allergic dermatoses, including atopic dermatitis and food sensitivities, frequently manifest as pruritus and subsequent hair loss, often in characteristic patterns.
- Bacterial (e.g., *Staphylococcus pseudintermedius*) or fungal (e.g., *Malassezia pachydermatis*) skin infections can cause alopecia, erythema, odor, and crusting, requiring targeted antimicrobial or antifungal therapy.
- Endocrine disorders, such as hypothyroidism or hyperadrenocorticism, can result in symmetrical coat thinning and other dermatological changes, necessitating hormonal assays for diagnosis.
- Physical factors like pressure sores or repetitive friction from collars or bedding can lead to localized hair breakage and alopecia.
- Persistent, severe, or rapidly worsening hair loss, especially when accompanied by systemic signs like collapse, seizures, severe gastrointestinal distress, or profound weakness, warrants immediate emergency veterinary intervention.

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**Hair loss in a dog can be mild or serious depending on the pattern, timing, and other signs. It may involve local irritation, discomfort, stress, injury, stomach upset, skin changes, or another medical problem. Call your veterinarian when signs are persistent, severe, or worsening.**

## What symptoms or causes should I watch for?

- **Parasites:** Fleas and mites can damage skin and hair.
- **Allergies:** Itching and licking can create bald patches.
- **Skin infection:** Bacteria or yeast may cause redness, odor, or crusting.
- **Hormone disease:** Some endocrine diseases cause coat thinning.
- **Pressure or friction:** Repeated rubbing can break hair.

## What can I safely do at home right now?

- **Keep your pet calm:** Use a quiet room and limit rough activity until you know what is happening.
- **Check the basics:** Look for appetite changes, water intake, bathroom habits, breathing, pain, and energy level.
- **Remove obvious risks:** Pick up unsafe food, plants, medication, trash, string, toys, or chemicals.
- **Record details:** Write down when it started, how often it happens, and what changed recently.
- **Call your vet:** A dog owner should ask for guidance if the sign continues or the pet seems unwell.

## When is this an emergency?

Go to an emergency veterinary clinic now if you notice:

- Trouble breathing, collapse, seizures, or severe weakness.
- Repeated vomiting, severe diarrhea, blood, or a swollen belly.
- Obvious pain, inability to walk normally, or crying when touched.
- Not eating, not drinking, or not urinating normally.
- Any rapidly worsening sign, especially in a puppy, kitten, senior pet, or chronically ill pet.

## What will my veterinarian check?

Your veterinarian will use the history and physical exam to narrow the cause. They may recommend lab work, urine testing, stool testing, imaging, skin or ear tests, or other diagnostics based on the sign.

## How can I reduce the risk next time?

Keep parasite control consistent and schedule an exam for bald spots, odor, sores, or spreading hair loss.

## Related veterinary guides

- [Why Is My Dog Scooting?](/knowledge/veterinary-medicine/parasitic-diseases/why-is-my-dog-scooting)
- Why Does My Dog's Breath Smell?
- [Why Is My Dog Drinking So Much Water?](/knowledge/veterinary-medicine/symptom-guides/why-is-my-dog-drinking-so-much-water)
- [Why Is My Dog Peeing So Much?](/knowledge/veterinary-medicine/symptom-guides/why-is-my-dog-peeing-so-much)

## Related Clinical & Scientific Guides

* [How To Treat Ringworm In Kids At Home](/knowledge/veterinary-medicine/parasitic-diseases/how-to-treat-ringworm-in-kids-at-home)
* [Dog Itchy Ears Mites](/knowledge/veterinary-medicine/parasitic-diseases/dog-itchy-ears-mites)
* [Side Effects Of Flea Medicine For Dogs](/knowledge/veterinary-medicine/parasitic-diseases/side-effects-of-flea-medicine-for-dogs)


## References

- [Companion Animal Parasite Council - Fleas](https://capcvet.org/guidelines/fleas/)
- [AVMA - Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)
- [AAHA - Senior Care Guidelines for Dogs and Cats](https://www.aaha.org/wp-content/uploads/2022/12/2023-aaha-senior-care-guidelines-for-dogs-and-cats.pdf)

*Disclaimer: This article is for educational and informational purposes only. It does not constitute medical advice, does not establish a vet-client-patient relationship, and should not replace an in-person evaluation by a licensed veterinarian.*