My dog's nose looks strange or discolored. What's causing this issue?

This does not look like typical demodectic mange. Typical would be skin lesions and loss of hair around the eyes and other parts of the body. Demeodectic and other manges can be diagnosed with a skin scrape. What I am seeing on your photos is depigmentation of the philtrum/nose and skin around the mouth. This could be a sign of bacterial infection, or an autoimmune disease, or possibly a fungal infection. This cannot be diagnosed via a photo, so you will need to take your dog to your veterinarian for an exam.

Given that it's gotten darker and has been there for almost a week, yes I do think it's worth getting checked out by a vet. It may be from an injury or it could be a skin infection. The vet can diagnose what is causing it and can treat Pasha.

He could have a skin infection or an allergic dermatitis. You could bathe him with a medicated dog shampoo and see if that helps. If not, have your vet take a look at him. He may need an antibiotic, anti-histamine, or a corticosteroid to help treat the problem.

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question about Princess. This discoloration and redness could be due to an injury, allergies, or infection. Without seeing her in person, I can't say what is going on. I'd have her seen by a vet in the morning. Best of luck.

Hello and thank you for contacting Petco Pet Education Center, formerly Petcoach. It could be due to acne development or other local allergic or inflammatory reaction. As long as this area is not painful and is not bothering your dog, you can monitor her at home for the weekend. However, if the area is sore or is bothering your dog, you should take her to your local vets tomorrow.

Thanks for using Petco Pet Education Center, formerly Petcoach! The little area of discoloration is not necessarily anything to worry about. I see this commonly with time with dark skinned animals. As long as the skin does not seem irritated and the discoloration does not happen on the nose itself, I am inclined to just continue to watch it. Apply a dab of children’s sunscreen lotion before she goes outside to protect that area from sunburn. Best wishes to you and Luna!

From the photos it appears that the lesion is affecting both the mucosa of his nose and also his skin. This could be some sort of deep bacterial infection or perhaps something like ringworm (which humans can get). It is also very concerning however for an autoimmune condition. I recommend to have a Bosco visit his veterinarian with in the next day for an exam. The doctor may try treatment or testing for an infection. The doctor may also recommend a biopsy. A biopsy is needed to diagnose an autoimmune condition. Best of luck. I hope this helps and please feel free to post any additional questions.