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My dog has a rash under her neck. Is it from her flea collar?

Updated On September 23rd, 2025

Pet's info: Dog | Boston Terrier | Female | 1 year and 8 months old | 21 lbs

I have a Boston Terrier that recently developed a rash under the face just below neck line. She is not scratching at the area. Using Seresto flea collar. On Royal Canin Urinary SO. Bathed weekly with either Furminator or Buddy Wash rosemary&mint . Not out side dog but does get exercised and walked outside for 30-40 minutes daily. Thank you for your answer/help

3 Answers

Most Helpful Answer

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Answered By David Darvishian

Veterinarian

Published on September 4th, 2017

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Macy. Not sure how long the Seresto flea collar has been on but it could be some local irritation from the collar. Other possibilities include a bacterial skin infection, trauma from scratching, fungal infection, mites, an internal organ problem, among many other things. If the condition worsens, persists, spreads, or is really itchy I would advise letting your vet take a look at Macy. They can get a detailed history, do a thorough exam, and then advise some tests if needed. Skin tests include skin scrape, woods lamp exam, fungal culture, skin cytology, etc. If they felt like this problem was due to an internal organ problem, they may advise some tests which could include fecal/blood/urine tests and maybe even some x-rays. Your vet can decide whether the Seresto collar is involved or not. If it is, I would report this to Bayer Animal Health or have your vet report it. Good luck with Macy.

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    Answered By Dr. Davis

    Veterinarian

    Published on September 5th, 2018

    I don’t see evidence of fleas either. This looks like a mild skin infection. I recommend bathing the area in medicated anti bacterial and anti fungal shampoo twice weekly and keep her out of the dirt if you can. This should improve with the baths. If it isn’t improving then a veterinary exam and probably a course of oral antibiotics may be needed. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Diamond.

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    Answered By David Darvishian

    Veterinarian

    Published on November 27th, 2017

    Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Bow. Sounds like he is having a contact dermatitis reaction to it. I would advise washing the neck and head area with Dawn dish soap to remove as much of the chemical as possible. Make sure you rinse the area very well, dried soap will cause even more scratching. If this doesn't stop the itching, then I would advise calling the manufacturer of the collar and telling them what is going on. They should help you with any vet bills from the use of this collar. Then I would take Bow to the vet and have him treated. He may need some cortisone or other medicine depending on what the affected areas look like, possibly an Elizabethan Collar also. A good lesson here is never use an over the counter flea product unless your vet advises it. Good luck

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