Comprehensive Guide to Dog Skin Conditions: Identification, Causes, and Treatments

Article Summary

• Skin health is extremely important for our dog’s well-being, and many skin conditions can look the same, so it's important to get a proper diagnosis.
• Damage to the skin can occur from cuts, bites, excessive scratching or underlying issues like allergies, hormonal disease or autoimmune disease.
• Common causes include parasites like fleas, mites or lice, skin allergies, fungal or bacterial infections, hormonal issues, autoimmune problems, and even skin cancer.
• Fleas can cause itchiness, scabs, fur loss or flea allergic dermatitis, and even if fleas cannot be spotted, appropriate flea prevention may still be needed.
• Yeast infections, ringworm, and pyoderma are often linked to damaged skin or underlying diseases, and bacterial infections can appear as spots, crusts, redness, or smelly discharge.
• Hormonal imbalances, such as hypothyroidism or Cushing’s disease, often lead to hair loss, thinning skin and other visible changes.
• Treatment may include topical therapies, antibiotics, anti-itch medication, anti-parasite products, diet changes, surgery, or management of chronic conditions.
• If your dog has itchy skin, fur loss or a non-healing wound, book a vet visit to get help early.

If your dog becomes uncomfortable, itchy or sore, it can be a stressful time for both you and your pet. The trouble is that there is a huge array of different skin conditions that can all cause similar signs. So, what could be bothering them?

We’ve put together our comprehensive guide to dog skin conditions to help you understand what might be troubling your canine companion and when to look for veterinary help.

Healthy skin

Your dog’s skin acts as a protective barrier to the outside world. It is designed to keep harmful intruders out, such as bacteria and yeast. The skin is also responsible for many other functions, including temperature regulation and stopping body fluids from escaping.

Let’s dive a little deeper.

Healthy skin is divided into three layers:

The epidermis (outermost layer) – this is the part we can see. It is covered in specialized cells called keratinocytes, which give it a protective surface that is constantly shed and renewed.

The dermis (middle layer) – important structures like hair root follicles and sebaceous (oil) glands are found in the dermis. These then exit up through the epidermis to the skin surface. The sebaceous glands secrete an oily substance known as sebum, which keeps your pet’s skin soft and flexible, adding extra protection to the body. Blood vessels are also found in the dermis.

The subcutis or hypodermis (innermost layer) – in this layer you will find fat and muscle. This subcutaneous fat is important for insulation and shock absorption, as well as being an energy reserve.

Good skin and coat condition is important, and not only because it will help your dog look their best! They also play a role in keeping your dog well.

As a complex organ, the skin can be affected by many factors, which may include your dog’s immune response (defence mechanisms) and their skin barrier, as well as the local microorganisms that naturally live on your dog’s skin.

If the skin becomes damaged, this balance is disturbed and normal skin microorganisms, such as bacteria and yeast, and even harmful pathogens (disease-causing microorganisms) can start to multiply and lead to skin problems.

Common canine skin conditions

As there can be a lot of similarities between different skin conditions, we would always recommend that you and your dog visit the veterinarian for an accurate diagnosis. 

Meanwhile, let’s take a look at some of the most commonly seen skin conditions in dogs, as well as what might cause them in the first place. Hopefully this information will give you confidence when chatting things through with your veterinarian.

Parasites

Parasites are a very common cause of skin disease in dogs, with fleas being the most common culprits. We know that creepy crawlies can be quite unpleasant to think about, but it’s important to understand the effects they can have on your pet’s skin. Thankfully, your veterinarian can recommend suitable anti-parasite products that help prevent some of the following problems in the first place.

Fleas

These small brown wingless creatures will rapidly reproduce on your pet. 

Their eggs fall off into your household, hatching out into tiny larvae. These will crawl into your carpet or gaps between floorboards, eating debris. They will then form cocoons called pupae which can sit undisturbed for several weeks before hatching out as adult fleas.

This whole process is known as the flea life cycle, which your vet can discuss with you further. As you can see, treating the environment, as well as your pet, is key to helping you reduce flea numbers faster and get on top of the problem. 

Signs of fleas – Dogs with fleas will often be itchy, but may also have scabs and areas of fur loss due to nibbling and scratching. They can be extremely itchy if your dog is allergic to flea saliva, known as flea allergic dermatitis. You may also see specks of black/brown flea dirt in your pet’s coat, as well as the fleas themselves. It is important to remember that you may not see live fleas on your pet. Because only small amounts of flea saliva can set off the allergic response, it is very common that flea-allergic pets have very few fleas on them. This is why your veterinarian may recommend appropriate flea prevention, even if fleas cannot be spotted.

Mites

Microscopic mites cause a skin condition known as mange. 

The most common types of mange are sarcoptic mange and demodectic mange. 

Dogs naturally carry low levels of the Demodex mite, and it doesn’t usually cause a problem, but in young or debilitated dogs (immune system not working well), its numbers can multiply more easily, leading to disease. The Sarcoptes mite, however, is infectious and can be spread through contact with infected animals to both your pets and you!

Signs of Mites – Demodex typically causes areas of non-itchy hair loss. Sarcoptes mites burrow in the skin, causing widespread intense itchiness, crusting and hair loss. 

Lice

Lice are tiny parasites that live on the skin surface, feeding on your dog’s blood. They are less common than fleas or mites and are not often found in dogs living in clean conditions, but it does happen. Lice are usually associated with overcrowded, unsanitary situations such as puppy farms.

Signs of Lice – Itchy, flaky or dry skin. Hair loss can also occur, and, if you look, you can see the lice and their eggs in your dog’s coat, which often stick to the hairs themselves.

Skin allergies

Atopic dermatitis is usually associated with environmental triggers like grass, pollens and house dust mites. 

As the name suggests, flea allergic dermatitis is due to an allergic reaction to fleas’ saliva. Food allergies are also a possibility in your dog, though not as likely, and are often reactions to common food proteins like beef and chicken.

It is not possible to prevent allergies from developing. Some breeds seem more prone than others and genetics are known to be a factor. If your dog suffers from allergies, they will need life-long management. Fortunately, with the right treatment, your dog can lead a happy, comfortable life.

Signs of Skin Allergies – Common signs include increased itchiness and repeat skin and ear infections. Your dog may have sores, scabs and inflamed skin. Dogs might also lick their paws to excess, leaving saliva staining on the fur. This makes their paws look pinky-brown in colour. If skin allergies are left untreated, your pet may develop changes in their skin’s colour and thickness. Affected dogs will often be seen scratching, nibbling and licking multiple times during the day and at night.

Fungal infections  

When the skin barrier is compromised, normal skin microorganisms can start to multiply. A common cause of yeast infection in dogs is Malassezia pachydermatis. This yeast lives on the skin of normal dogs at low levels, but when the skin is damaged through issues like allergies, its levels begin to rise.

Managing any underlying skin issues will help to keep yeast infections under control. Regularly cleaning and drying between skin folds will also help to prevent them from developing in these problem areas.

A different type of fungal infection is ringworm, also known as dermatophytosis. This is spread by direct contact with infected animals or a contaminated environment, and can be passed on to humans as well.

Signs of fungal infection – Dogs with Malassezia dermatitis may have yeasty-smelling skin and a greasy coat. They are often itchy with inflamed, scaly skin. They might also have some dark brown discharge present at the nail bed and discoloured nails. Dogs with ringworm will usually have circular patches of hair loss, with scaly inflamed skin.

Bacterial infections

Secondary bacterial skin infections (pyoderma) are also more common in dogs that have other underlying conditions, which affect the quality of their skin barrier and its protective nature. This could be diseases like allergies or autoimmune problems, but we can also see it in dogs that have excessive facial folds, which act as a trap for warmth and moisture. 

Managing any underlying skin issues is key to keep bacterial infections under control, in addition to topical and/or oral antimicrobial treatment. Though antimicrobials or antiseptics will be needed to treat an active infection, you’ll only be able to prevent future ones if the underlying cause is treated as well. Regularly cleaning and drying your dog’s skin folds will also help. 

Signs of bacterial infection – this can vary depending on severity. It is possible to see small or well-defined areas of infection, like in hot spots (acute moist dermatitis). But dogs can have more widespread skin infections. Spots or pustules (pus filled spots) might be present, or you could notice skin crusts, redness and increased itchiness. Moist patches of skin or smelly discharge might also be seen, which can be sore for your furry family member.

Hormonal issues (endocrine disease)

Skin changes are common in dogs that have hormonal issues. Hypothyroidism (decreased thyroid hormone) causes thinning of the fur, as well as weight gain and lethargy. Affected dogs usually have hair loss down both sides of their body known as flank alopecia. They are also prone to skin infections (pyoderma).

Hyperadrenocorticism (Cushing’s disease) is another example, where the body has started overproduction of steroid hormones. This can be caused by a small tumour on the adrenal gland or in the brain, or due to long-term treatment with steroids. Thinning of the skin, hair loss and pigment changes are usually noticed. Many owners report an increase in their dog’s thirst, appetite and urine production.  

Fluctuations in sex hormones can also cause coat and skin changes, which can often be prevented or managed through neutering. 

Signs of hormonal issues - Skin and coat changes in animals with endocrine disease are typically not itchy (unless they have secondary infections). Hair loss or thinning in these dogs tends to be symmetrical in appearance and dogs will show other symptoms beyond the skin. 

Autoimmune problems

When a dog has an autoimmune disease, it means that their immune system has gone into overdrive and has started attacking healthy cells in the body. There are a few different causes of autoimmune skin problems in dogs, including Pemphigus Foliaceus and Discoid Lupus Erythematosus (DLE).  We don’t always know what leads to this exaggerated immune reaction, but in some dogs, autoimmune disease can be triggered by sun exposure or certain medications. 

Signs of autoimmune disease – These include sores, scabs, skin thickening, hair loss, painful blisters and ulcers (skin wounds). Secondary infections are common. 

Cancer

We understand that many pet owners become frightened when they hear the word cancer. Skin cancer in dogs, however, can often be treated if detected early enough. 

Common examples include mast cell tumours, malignant melanoma and squamous cell carcinoma.

Your vet will need to perform further tests to give you a diagnosis, as many skin lumps can look the same. When it comes to skin cancer, it may not even look like a lump, it sometimes looks like a wound that doesn’t heal. 

This will also allow your vet to come up with the best treatment plan, which may involve surgery, with or without chemotherapy, and radiotherapy.

Some skin cancers are linked to sun exposure (UV radiation). Dogs that have no fur, thin fur or white fur can have pet-safe sun lotion applied to protect them, especially on sensitive areas, such as the nose, ear tips and hairless areas, and even more so if they are pink-skinned. You should also consider stopping them from sunbathing during the heat of the day.

Signs of skin cancer – A lump or swelling in the skin, changes in skin colour, inflamed areas of skin and wounds that don’t heal can all be signs of skin cancer in your pet. 

What should I do if my dog has a skin condition?

It can be distressing to see your canine companion losing their hair, or becoming so itchy that they are uncomfortable. Luckily, your veterinarian is on hand to help, so make sure to get your dog booked in for an examination. Your veterinarian will need to perform a few tests to diagnose the problem, as there are so many conditions that can affect your pet’s skin, but they will talk you through this as they go along. 

Keep in mind that diagnosing and managing skin conditions can be a lengthy and frustrating process for both you and your veterinarian, so make sure you share your concerns. 

Many skin complaints can appear similar to the untrained eye, so getting a professional to diagnose your dog is essential. They can then prescribe safe and effective medications to help manage the problem.  

How are dog skin conditions treated?

Due to the wide array of different skin conditions in dogs, there is also a wide array of different treatment options! 

Depending on the diagnosis, your pet may need one or more of the following for their skin complaint:

• Topical treatment - medicated shampoo, ear drops, wipes or cream can help with fungal and bacterial infections, as well as calm inflamed skin.
• Antibiotics – oral antibiotics may be needed to resolve deeper bacterial infections and should always be administered according to your vet’s recommendations.
• Anti-itch medication –There is a range of medications that can help soothe your dog’s itchiness, including steroids, JAK inhibitors, monoclonal antibodies and calcineurin inhibitors. Your veterinarian will help you find out what works best for them.
• Anti-parasite treatment – topical spot-on treatments or oral tablets may be prescribed to help treat and prevent parasites. Especially in dogs that are suspected to have flea allergy.
• Changes in diet – providing a better-quality diet or supplementing your pet with omega-3 fatty acids can help in some cases. Alternatively, your dog may require a strict hypoallergenic or novel protein diet if they are diagnosed with food allergies.
• Management of underlying health conditions – animals with autoimmune disease, hypothyroidism and Cushing’s disease will require treatment to improve skin conditions. This treatment is likely to be life-long.
• Surgery – Some conditions like cancer or chronic ear infections may need to be treated through surgery.

Skin health is extremely important for our dog’s well-being. If your pet doesn’t seem right, you must get them checked by your veterinarian. Many skin conditions can look the same, so it's important to get a proper diagnosis. 

Sadly, some owners leave things too long before getting advice, which can make problems harder to diagnose and treat. Your veterinarian is there to work out the best course of action for you and your pet, so don’t be afraid to seek help.