If your dog scratches non-stop, has lost hair in patches, has red skin or gives off a bad smell, what they need is a dermatological assessment. Veterinary dermatology is the branch that deals with the skin, hair, nails and ears: the largest organ in the body and also one of the most common reasons for a visit. The good news is that almost every skin problem can be controlled well once its real cause is identified, and that requires a diagnosis made by a professional, never from a distance.
The most common skin conditions in dogs
The skin reacts in very similar ways to very different problems: itching, redness, hair loss or crusting can appear in an allergy, an infection or a parasite alike. That is why a single sign does not point to one cause, and self-diagnosis is best avoided. These are some of the situations that most often bring a dog to the dermatology clinic.
| Problem | Characteristic sign |
|---|---|
| Allergic dermatitis | Intense, persistent itching, especially on paws, armpits, groin and face. |
| Bacterial infection (pyoderma) | Pimples, pustules, crusts and red skin areas with a bad smell. |
| Fungal infection (dermatophytosis) | Circular areas of hair loss with scaling. |
| Skin parasites (mange, fleas) | Itching, crusts and lesions from scratching; sometimes localised hair loss. |
| Otitis | Head shaking, ear odour, redness and discharge. |
| Hormonal disorders | Symmetrical hair loss without itching, thin skin and coat changes. |
As you can see, the most common skin problems in pets share symptoms but require completely different treatments. That is why the goal of dermatology is not just to relieve the itch, but to find and treat what is causing it.
Atopic dermatitis and allergies
Atopic dermatitis is one of the most common causes of chronic itching in dogs. It is a predisposition that makes the animal react excessively to substances in the environment that would normally be harmless: pollens, house dust mites, environmental fungi or certain foods. It is not a disease that is "cured" overnight, but a condition that is controlled throughout the animal's life.
Alongside atopy, two other very common forms of allergy are flea bite allergy —in which a single bite can trigger disproportionate itching— and food allergy or intolerance. Telling them apart is one of the classic challenges in dermatology, because they often coexist and overlap. In practice, an allergic dog may at the same time have a secondary bacterial or fungal infection that worsens the picture, which means several things have to be treated at once.
To learn more about the signs and day-to-day management of these conditions, you can read our guide on dermatitis in dogs, which complements this specialist approach.
Fungal infections and skin parasites
Not all itching is allergic. A significant share of dermatology visits has an infectious or parasitic origin, and here laboratory diagnosis is decisive. Fungi (such as those responsible for dermatophytosis, the well-known "ringworm") cause areas of hair loss and scaling, and they also matter because some can affect the people in the household.
Among parasites, the various forms of mange produce itching that can be very intense, and fleas, besides their direct nuisance, are the cause of one of the most common skin allergies. Identifying the exact culprit —whether a mite, a fungus or a bacterium— completely changes the treatment plan, which is why it should not be done "by eye". Good baseline parasite control is, in many cases, the first line of prevention for these problems.
A single sign —itching, hair loss or redness— may be due to an allergy, an infection, a parasite or a hormonal problem. Only a diagnosis tells which one it is, and the whole treatment depends on it.
“The skin is the mirror of your dog's health. When something changes there, it's almost always telling us something worth checking.”
How a skin problem is diagnosed
Dermatological diagnosis is detective work. It is not based on a single test, but on combining a good clinical history with examination and laboratory techniques that allow causes to be ruled out one by one until the right one is reached. These are the usual steps:
Clinical history and examination. The vet asks about the age of onset, the seasonality of the itching, the diet, the antiparasitic products you use and whether other animals or people are affected. They then examine in detail the pattern and distribution of the lesions, which already provide many clues.
Skin tests and cytology. The skin scraping looks for parasites such as mange mites; cytology involves taking a sample from the surface of the skin or ear and examining it under the microscope to detect bacteria, yeasts or inflammatory cells. When needed, cultures identify fungi or the exact germ, and a biopsy is reserved for specific cases.
Exclusion tests. Where food allergy is suspected, an elimination diet is used for several weeks; in atopy, specific allergy tests may be considered. This exclusion-based approach explains why a dermatological diagnosis sometimes takes time: what it is not is gradually ruled out to confirm what it is. In conditions that affect the whole body, working together with veterinary internal medicine helps rule out hormonal or systemic causes.
General management: treat the cause, not just the symptom
Once the cause has been identified, dermatological management usually combines several tools: skin care with appropriate products, control of secondary infections, management of the itching and, above all, treatment of the underlying problem. In chronic diseases such as atopy, the realistic goal is not to eliminate the problem forever, but to keep the dog comfortable, with as little medication as possible and good skin condition in the long term.
This requires consistency on your part: follow-up checks, seasonal adjustments and communication with your vet when something changes. Assess each case with your vet; the right treatment depends on each animal's age, weight, health status and history.
When to see a veterinary dermatologist
Your regular vet resolves most skin problems. Referral to a more specialised dermatological approach makes sense above all when the condition is recurrent, chronic or unresponsive to the first treatments. It is worth considering a dermatological assessment if you notice:
Itching that does not improve or keeps coming back; skin infections or otitis in dogs that recur every few weeks or months; extensive or symmetrical hair loss; wounds that do not heal; significant changes in the colour, thickness or smell of the skin; or lesions that also affect the people living with the animal. In all these cases, the sooner the correct diagnosis is reached, the sooner the cycle of relapses is broken.
In cats, skin problems also exist, although they often show up more discreetly —excessive grooming, small crusts— and deserve the same attention.
Frequently asked questions
Why does my dog scratch so much if I can't see any fleas?
Itching is not always caused by visible parasites. Atopic dermatitis, food allergies, bacterial or fungal infections and some microscopic parasites produce intense itching without any fleas being visible to the naked eye. Identifying the exact cause requires an examination and skin tests; that is why the most useful thing is to come to the clinic rather than trying products at random.
Can my dog's skin diseases be passed to people?
Some can. Certain fungi (such as ringworm) and some parasites can affect the people in the home, while most allergies are not contagious. Since it is impossible to tell at a glance what kind of problem it is, when lesions also appear on family members it is best to consult the vet and, in parallel, a doctor.
Can atopic dermatitis be cured?
Atopic dermatitis cannot be cured permanently, but it can be controlled very well. With a proper diagnosis and a long-term management plan, most dogs lead a comfortable life with healthy skin. The key is consistency in follow-up and the adjustments your vet recommends over time.
How long does it take to diagnose a skin problem?
It depends on the case. Some infections or parasites are identified in the same visit with a cytology or a scraping, while allergies usually require exclusion tests that may last several weeks, such as elimination diets. This time is not a delay, but part of the method: causes are ruled out to confirm the real one.
Care for your pet's skin at Clínica Veterinaria Somo
At Clínica Veterinaria Somo, in Cantabria, we approach your dog's skin problems with an orderly diagnostic method: clinical history, examination and the tests needed to treat the cause and not just the symptom. If your pet scratches non-stop or has a skin problem that never quite resolves, get in touch with us through our contact page or call us on 942 51 00 66. The sooner we reach the diagnosis, the sooner they will feel better.
