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My dog has severe fleas, hair loss, scratching, and a lump. Help!

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed Large (61lb +) | Female | spayed | 2 years and 1 month old | 70 lbs

Hey, coco has fleas really bad and I’ve tried just about everything under the sun to fix it. She’s lost her hair on her ears legs and back, and she won’t stop scratching or biting. Now she has a big hard lump on her back where she chews at and it sometimes while she walks she shakes her back legs. How do I get her hair back fast and what about the lump?

4 Answers

Most Helpful Answer

Chad Brown, DVM

Answered By Chad Brown, DVM

Veterinarian

Published on August 3rd, 2018

Hello and thank you very much for your question. Fleas can be so frustrating and I sympathize with what you were going through.

What has to happen for your dog to heal and for the lump to possibly go down, Is for the itch cycle and the inflammation to be stopped.

A visit to the local veterinarian is a must in this situation because they will have strong prescription strength flea preventative as well as steroids that can be given to your dog to stop the fleas and therefore the dermatitis that’s associated with their biting. I urge you not to use any further over-the-counter flea preventative or skin medications without the approval from your veterinarian. This will only delay the healing and may exacerbate the problem.

The lump should go down with time as long as the fleas are killed and the inflammation of the skin is controlled. But, if the lamp does not go away within the next two months, you may want to have your veterinarian take a biopsy of it just to see if it is indeed even related to the fleas. Does that make sense?

I appreciate you reaching out to our service. I hope I’ve helped you today.
Vote Icon1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Answered By Ricardo Fernandez, DVM

    Veterinarian, Veterinary Oncology Resident

    Published on October 16th, 2017

    Thanks for using Petco Pet Education Center, formerly Petcoach! Poor Patchez! Flea allergy can be so stressful to deal with. The main thing is getting rid of fleas effectively as that is the inciting cause driving the itchiness resulting in scratching and self-traumatic lesions like that. If she is already on a flea preventative, then you could consider switching to a different product. There are many great product in the market such as Frontline and Bravecto, among others.

    Also, it is important to vacuum the house and all things that have contact with Patchez. Try this for 1-3 months and if does not make a difference, she may have another type of allergy such as a food allergy or environmental allergy.

    Good luck and thanks for letting us take care of you today!

    Vote Icon

    1Pet Parents found this answer helpful

  • Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

    Veterinarian

    Published on September 25th, 2018

    This is probably due to an allergy, although it could also be infection or mites.
    First of all, in order to rule out skin parasites, you will need to treat with a high quality flea treatment, then ask the vet to perform a skin scrape - this might reveal an infection or a mite infestation.
    If all of those came back negative, the next step is to treat the allergy symptomatically and try to discover the cause of the allergy.
    Three main type of allergies are usually affecting pets: food allergies, flea and parasite related ones and environmental type (allergens coming from trees, pollens, dust etc etc).
    Some medications can be given by the vet in order to repair any possible skin lesions (like steroids and antibiotics).
    Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.

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    1Pet Parents found this answer helpful

  • Answered By Dr. Leigh, DVM

    Veterinarian

    Published on June 5th, 2017

    She could have a bacterial skin infection associated with the flea allergy dermatitis. Since it is not responding to the treatments that you have tried, she should be examined by a vet for treatment. She may need a corticosteroid, antibiotic, and an anti-histamine to treat. Your vet can also recommend an effective flea control regime to help prevent fleas. The best thing is to use a monthly flea prevention, like NexGard, Frontline, Advantage to help control the fleas.

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    1Pet Parents found this answer helpful

Smart Picks for Smart Questions

Vet Q & A
My dog's flea allergy causes itchy lumps. What treatments work?
Flea allergies can be very difficult to manage, I completely sympathize with your frustrations and below I will try to suggest some more tactics for you to employ; Treat your home for fleas as fleas actually spend more of they life cycle off of your dog then on it 3 solid months of topical treatment to end the flea life cycle Skin health supplements such as vitamin e and fish oils http://www.vrshealth.com/canine-products/?petcoach=1977955 Benadryl has been known to help provide temporary relief pets when they are facing itchy skin from allergies https://www.petcoach.co/canigive/dog/benadryl/ https://www.petcoach.co/article/5-tips-to-get-rid-of-fleas/ I hope these tactics help you and Celeste, and please feel free to post any further questions you may have here on Petcoach!
Updated on September 23rd, 2025
Food & Nutrition
My dog's flea allergy bumps are still huge after treatment. What now?
Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Brutus! After a bad flea infestation and reaction it is best to have your Vet treat the skin with a course of antibiotics and steroids. A skin infection usually results from all the scratching from the fleas. This is the quickest way to resolving Brutus's skin issues and to make him feel better. You can try the cream but I wouldn't want him to lick it and it will get stuck in his fur. Plus that is a very large area for cream. I hope this helps and I wish Brutus the best!
Updated on September 23rd, 2025
Training & Behavior
My dog has large, growing bumps on his rump. Is it an emergency?
These lumps are not typical of a flea allergy dermatitis. That typically is just a superficial rash with itching, hair loss, scabs, etc. These lumps are concerning. Your pet may have developed abscesses which are deeper infections that form pockets of pus or infectious fluid. This is worth a trip to the vet for a recheck. I do not feel that it is a life threatening emergency, but it should be addressed by your veterinarian as soon as regular business hours resume. Your pet may need prescription antibiotics, the lumps may need to be aspirated or checked with a needle and if they are full of pus, they should be drained. Please have your vet recheck him as soon as possible,
Updated on September 23rd, 2025
Vet Q & A
My dog has itchy skin, rashes, lumps, and hair loss. What to do?
Thanks for using Petco Pet Education Center, formerly Petcoach! This looks like it could be skin allergies. It really comes down to figuring out what is causing his allergies so that they can be treated or the specific allergen avoided. 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! There is really nothing specific you can try at home other than bathing him with a medicated shampoo you can get at your local pet store. This shampoo should contain chlorehexidine. In reality though, this is unlikely to resolve this issue completely. Good luck and have a good day!
Updated on September 23rd, 2025
Vet Q & A
Why is my dog so itchy with dandruff, scabs, and an oozing lump?
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 her allergies so that they can be treated or the specific allergen avoided. The lump may actually be something like a cyst. 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!
Updated on September 23rd, 2025
Health & Wellness
My dog has rashes, chews, and a hard nipple lump. What to do?
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 her allergies so that they can be treated or the specific allergen avoided. 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! The lump could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!
Updated on September 23rd, 2025
Vet Q & A
My dog has scabs, bumps & hair loss after flea treatment. Why?
Hello. I am sorry that Bailey has these issues. Often-times fleas/tick infestations can lead to secondary infections which need antibiotics to treat. This could be the 'bumps' on her side- they could be little pustules of infection. Without seeing her we cannot tell for sure. Also, after removing parasites it can take some time for the skin to calm down enough for the itching to stop. If she was covered in fleas/ticks, it is also possible she also has mange, which may require different medication to treat. The scabs and fur loss/thinning is likely due to itching/scratching and self-trauma from the irritation. Keep her clean and dry, and if you can bring her to a vet to ensure all of the parasites are gone, and to check if antibiotics are needed. Flea treatment also needs to be repeated every 2 weeks for 3 treatments, to ensure you kill the fleas that have hatched from the eggs (the eggs survive your bath). Good luck with Bailey!
Updated on September 23rd, 2025

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