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My dog is itchy with a rash and blood blister. What should I do?

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed | Male | unneutered | 6 months and 19 days old | 137 lbs

Charlie has been pretty itchy the last couple weeks and Benadryl seems to have helped the last 3 days. However, I noticed that he has given himself a little blood blister next to his nipple. Do I need to worry about that at all? And he looks like he’s got a slight rash going on, so I’ve given him a bath with antibacterial shampoo and anti itch conditioner. Is there something else I should be doing?

1 Answer

Most Helpful Answer

Ricardo Fernandez, DVM

Answered By Ricardo Fernandez, DVM

Veterinarian, Veterinary Oncology Resident

Published on August 14th, 2018

Thanks for using Petco Pet Education Center, formerly Petcoach! This is possibly due to allergies. It really comes down to figuring out what is causing his allergies so that they can be treated or the specific allergen avoided. A secondary infection is likely and also needs to be addressed. I would not be worried about the lesion next to the nipple.

There are many things that can cause allergies though in most cases they can be broken down into 3 big categories: flea, food and environmental allergies.

Allergies are usually worked up in a stepwise fashion starting with flea allergies as this is the easiest and cheapest to take care of. If not on a flea preventative, then it would be a good idea to get started on one. If already on one then it would be a good idea to change to something else (there are many new products out in the market).

If not improved in 1-3 months then it is time to move on and check for food allergies by switching to a novel diet (new protein and new carbohydrate). If that does not seem to be the issue then you are left out having to check for environmental allergies which require blood and/or skin tests.

Allergies can be very frustrating to deal with at first but so rewarding at the end when we are able to treat them effectively!
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