Petco Text Logo
Petco Pet Logo

My dog's scaly black spots are spreading. Is it fungus? How to treat?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | spayed | 10 years and 5 months old | 19 lbs

My dog started out with just a scaly spot on her back. The spot was black. Now they have spread over her back. They cleared a lot when bathed in oatmeal, but our groomer said she thinks she has a fungus. How should I treat this?

2 Answers

Most Helpful Answer

Image profile

Answered By Jenna Beyer, DVM, MBA, cVMA

Veterinarian, Certified Veterinary Acupuncturist

Published on August 11th, 2017

There can be many causes of increased pigmentation in dogs, mostly relating to chronic inflammation. This can be caused by fleas, mange, lice, infections (bacterial or yeast), ringworm, allergies, among others. If the spots seem to be increasing, I recommend that Sophie be evaluated by a veterinarian. Also, make sure she is on a good flea preventative (topicals should not be applied for 3 days before or after bathing to ensure good absorption). While you wait for your vet appointment, you can try a medicated shampoo like Dechra MalAcetic Ultra Shampoo - lather on the skin, let it sit for 5 minutes, then rinse thoroughly.

Vote icon

1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Image profile

    Answered By Linda G, MS, DVM

    Veterinarian

    Published on January 30th, 2019

    Hello. Obsessively licking of the paws is the hallmark of an allergic response to something in Sophie's environment. It could be something she in in contact with or something she is breathing in, a condition called atopy. Food allergies are an unlikely cause. The black spots are also a result of her allergies. The more she licks her skin, the darker it can become as melanin cells are deposited. You may be seeing something similar to blackheads, too. We have many ways of dealing with allergies, from diet changes ( least likely to work ), to allergy desensitization ( takes time to work ), to targeted immunotherapy products like Apoquel & Cytopoint. Talk with your vet as to what might work best for Sophie. Thanks for using Petco Pet Education Center, formerly Petcoach.

    Vote icon

    1Pet Parents found this answer helpful

See More Answers

Related Questions

Petco Pet Education Center
Health & Wellbeing
My girl has been having her skin turn black in areas. What can i do? There has to be a way to reverse this right?
This is due usually to a chronic type of inflammation, which could be caused by yeast skin proliferation for example. I would recommend, first of all, in order to rule out skin parasites, to treat with a high quality flea treatment, then ask the vet to perform a skin scrape or similar skin tests - this might reveal an infection or a mite (or different type) infestation. If all of those came back negative, the next step is to consider allergies as possible causes. 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). Shampoo are porven to be quite effective in these cases and medicated ones (like Malaseb) can be prescribed. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultati
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello, I have a Wire Hair Fox Terrier who has awful allergies. Her skin seems to have a black coating, for lack of a better word, on several spots of her body. Is this common for types of fleas, mites or skin infections?
She could have a skin infection, mites, fleas, ringworm, allergic dermatitis, etc. Your vet can do a skin scrape, cytology, or culture to help diagnose and then prescribe medications to treat the problem. She may need an antibiotic, anti-histamine, corticosteroid, or other medications depending on the cause. Make sure to treat her with a monthly flea medication like NexGard, Frontline, Advantage, or Revolution to prevent fleas.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
my dog has black spots on her skin that appear crusty but also seem to have a black string like center. have used frontline, flea shampoo, and spray with no luck in getting rid of the spots. Have seen no live fleas but there are often small black spe
Skin problems can have a variety causes. Fleas or other insects can cause irritation that can persist even after the fleas are gone. Treating the environment for fleas is also vital in eliminating the problem. Other causes for skin trouble can include bacterial or fungal infections and allergies to environmental substances and/or food. A dog may have a little sensitivity to some of these but not show any symptoms until they are confronted by several at once. Ideally, I would get your dog in to see the vet for an exam. Your vet may suggest a food trial with a food that has a novel protein source, one that your dog has never been exposed to, such as venison or duck. Proteins in food are the primary reasons for food allergies to occur in dogs.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Is black pigmentation on hind legs normal or could it be something else? Usually the pigmentation disappears on and off. The vet has checked it once and said that it could be yeast infection or her anal gland needs to be emptied. Can you offer som
Hello there. Great question! Hyperpigmentation can be caused by many different things: 1. Hypothyroidism (low functioning thyroid) – Up to 33% of dogs diagnosed with hypothyroidism showed signs of hyperpigmentation as one of their symptoms 2. Systemic Lupus Erythematosus – Some dogs diagnosed with lupus 3. Allergies – If your dog experiences allergies he may also develop hyperpigmented areas on his skin 4. Malassezia – Is a yeast infection that often has hyperpigmentation as a symptom 5. Demodicosis (skin mites) – Is caused by a mite and is a lesser known cause of hyperpigmentation Pseudo-Cushing’s Syndrome – Is an endocrine disorder that is common in dogs middle age and older and can have hyperpigmentation as a result The skin may go back to normal color if you can treat the underlying cause. That would entail some advanced testing with your vet. What you can do is try to used a medicated shampoo like Malaseb. http://www.allivet.com/p-299-malaseb-shampoo.aspx?g
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
I've noticed little black kind of oily spots on my malteses lower abdomen between the legs and at bottom part of nipples that attaches to skin.She also has been obsessively licking her paws.She does not have fleas.what could this be?
Hello. Obsessively licking of the paws is the hallmark of an allergic response to something in Sophie's environment. It could be something she in in contact with or something she is breathing in, a condition called atopy. Food allergies are an unlikely cause. The black spots are also a result of her allergies. The more she licks her skin, the darker it can become as melanin cells are deposited. You may be seeing something similar to blackheads, too. We have many ways of dealing with allergies, from diet changes ( least likely to work ), to allergy desensitization ( takes time to work ), to targeted immunotherapy products like Apoquel & Cytopoint. Talk with your vet as to what might work best for Sophie. Thanks for using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My 11years old female dog has very itchy flaky ...and the patches are black. When the spots are being scratched the skin fall off like dandruff but black
Poor Sweety! There are a number of different things that can cause itchy, flaky skin - the black color is likely pigmentation due to chronic scratching in these areas. Some common possibilities would include allergies (food allergies, or an allergy to something in the environment), fleas, a bacterial or fungal skin infection, or skin mites (mange). Since I see that Sweety is an older dog, it's also possible that she has a hormonal problem like hypothyroidism or Cushing's disease that is contributing to her skin problems. Treatment will depend on what the underlying problem is, so I would recommend taking her to the vet for an exam as soon as you are able to. He/she can do some simple skin tests as well as blood work if needed to help diagnose the problem and get her started on appropriate medication to treat it.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog has been itching for weeks and now has developed patches of baldness on her chest and head. I have tried to bathe her once with curaseb. Now she is rubbing all over the carpet. I feed her grain free food. Her ears seem to be bothering her. The
Itchy skin is often due to the following things: 1) Allergies - this can happen suddenly and is usually due to an environmental (i.e pollen) cause. 2) External parasites - fleas, lice and mites can all cause intense itching. It's good to check him for fleas and get treatment if needed. Otherwise a veterinarian will need to check for mites (mange) and prescribe treatment. 3) Over-bathing, or using the wrong product for bathing - Bathing too often can cause the skin to get dry and irritated. Dogs should normally be bathed no more than once a month with a shampoo that is labeled for dogs. If you bathe more than that, or use a shampoo or soap that is meant for people, then you could be damaging the normal protective barrier of the skin. One thing you can do for now to relieve itchy skin, is give a bath with cool water using an oatmeal or aloe shampoo. You can get these shampoos at the pet store. I hope this helps you to identify the problem. I think it will be worthwhile to
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog has really small black dots on her skin, there are also little flakes coming off but she isn’t experiencing any itching.
Hi, thanks for using Boop by Petco! The picture looks like comedones. How old is Sophie? Comedones are dilated hair follicles which can be from a bacterial infection, demodex (non-contagious mite) and dermatophyte (ringworm). These causes are diagnosed with skin scrapings and cytology, and possibly fungal cultures. In older dogs, hormonal diseases such as Cushing’s disease and hypothyroidism can also cause comedones and may be diagnosed by blood testing. In mildly affected animals, topical treatment with benzoyl peroxide gel perimay be helpful. Antiseborrheic shampoos (sulfur/salicylic acids or, in severe cases, benzoyl peroxide) may be helpful for more extensive lesions. Treatment of any secondary bacterial infection with antibiotics is also important. Ruling out hormonal disease should also be done. I hope this help!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hi, I would like to see if anyone could explain to me what's these black spots/patches growing on my 11 year old toy poodle? There is no odor and it's not itchy. It used to only be on her lower back, but it have spread to random patches of her back.
Sometimes these little brown patches are minor bacterial infections although they can also be related to allergies or endocrine disease. You may try washing her in a medicated dog shampoo once a week to see if that helps to clear it up. Make sure the shampoo does not overly dry her skin. If the spots don’t go away or if they get worse, have her see her veterinarian. I hope this is helpful and please feel free to post any additional questions.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hi. I want to know why my dog has a bunch of black spots on her skin. I read that it could be hyper pigmentation but i'm not so cure. It has gotten worse. A few months ago she had two big black spots on her skin and now she has 3 plus little ones all
It’s difficult to know how to advise without a photo. Pets can get more dark pigment on their skin as they age. Other causes of pigmentation our inflammation, allergies, drama and minor infection’s. Try to get a photo and repost as this may lead to better advice. Thank you for using Boop by Petco.
Updated on September 24th, 2025
image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Book Now

Sponsored