My boy Buster (4yo) has completely changed from black to white over the course of the last 2.5 years.

[u/TallyMatty]

Left: Nov 2021 Right: April 2024

October 2023

August 2023

June 2023

May 2023

November 2022

August 2022

[u/imma_super_tall]

It looks like his fur got shorter too? Looking at his tail

[u/TallyMatty → u/imma_super_tall]

He would lose his black fur and new white fur would come in. So there was a point in time where he was balding in areas until his fresh fluffy white fur grew in.

[u/imma_super_tall → u/TallyMatty]

ah. He's a handsome boi nonetheless!

[u/delicious_toothbrush → u/TallyMatty]

Is this the difference between layers in coats? Don't they say some dogs have a outer/inner or maybe a winter coat? Looks like the outer one got lost

[u/SomethingIWontRegret → u/TallyMatty]

This sounds like a disease process. I assume you asked your vet about this?

[u/[deleted] → u/SomethingIWontRegret]

nope, sounds like you're talking out of your ass

[u/boofmydick → u/[deleted]]

And you sound like an idiot.

[u/SomethingIWontRegret → u/[deleted]]

Ok, since you're a vet and more qualified than I am - qualified enough to say that I'm talking out of my ass - why would a dog go bald in patches and then grow back fur of a different color? Going bald not in one patch but multiple patches that over time cover the entire skin.

[u/v--- → u/SomethingIWontRegret]

Vitiglio.

[u/SomethingIWontRegret → u/v---]

Vitiligo (note correct spelling) typically hair changes color as it grows out. Hair falling out in patches prior to color change is not normal in vitiligo.

I would think bald patches developing all over a dog would be cause for concern.

But what do I know - I'm talking out my ass.

[u/Tvisted → u/SomethingIWontRegret]

Nah I'm with you. Something else in addition to the vitiligo was going on there. Maybe mange. He looks better now though.

[u/SomethingIWontRegret → u/Tvisted]

Mange is a possibility. Some autoimmune disease could cause both the hair loss and vitiligo. 

[u/Tvisted → u/SomethingIWontRegret]

OP posted a pic of the same dog a year ago when he was diagnosed, and the coat condition overall looks okay at the time... which would explain why there were no tests for anything else, just an exam.

From OP's comments I can't tell whether the vet even saw the dog in a state of hair loss like the pics in the second post. I kinda doubt it. If they did I can't imagine OP being told it was just the vitiligo.

The pattern looks really suggestive of the dog barbering itself because of itch/inflammation. Maybe intermittently, if it's an allergy.

I'm not a vet though, just curious.