Home » Symptoms » Dog Symptoms A-Z » Crusts

Crusts in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Are you unsure what is wrong with your pet? Feel free to use our symptom checker for more clarity.

Crusts in dogs are hardened, often scabby skin changes that form on the skin surface as a result of injuries, infections, or inflammatory conditions. They occur when blood, serumSerum is the liquid part of the blood that remains after coagulation. It does not contain blood cells or coagulation factors, but many other proteins, antibody and electrolytes. Serum is used in diagnostics for a variety of blood tests., or pus dries out and forms a protective layer over a wound.

Can Occur with the Following Diseases:

Basics and possible causes

A dog’s skin serves as a barrier against external influences and protects against infections and injuries. If this barrier is damaged, whether by scratches, bites, or other injuries, inflammation of the skin can occur. As a result, the body produces fluids such as serumSerum is the liquid part of the blood that remains after coagulation. It does not contain blood cells or coagulation factors, but many other proteins, antibody and electrolytes. Serum is used in diagnostics for a variety of blood tests. or blood, which form crusts when they dry.

Infections caused by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease., fungi, or parasites are common causes of crust formation. A bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., such as pyoderma, can occur when bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. penetrate the skin and cause inflammation. Fungal infections, such as those caused by dermatophytes, can also attack the skin and cause crusts.

ParasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. infections such as mange caused by mites can also lead to crusts. Mites burrow into the skin and triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. an immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens. that leads to severe itching and scratching, which ultimately promotes crust formation.

Allergic reactions to environmental substances, food, or medications can also be the cause of crusts. In the case of allergies, the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. overreacts and causes inflammation and itching, which can lead to scratching and crusts.

Autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus., in which the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. mistakenly attacks the body’s own cells, can also cause skin changes and crust formation. Examples include diseases such as lupus or pemphigus.

Typical accompanying symptoms

Itching: Severe itching often accompanies crust formation, causing the dog to scratch or bite frequently.
Redness and Swelling: Inflamed skin areas are often red and swollen, indicating a reaction of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body..
Hair loss: Hair loss can occur in the affected areas because the skin is damaged and the hair can no longer hold properly.
Pain: The dog may experience pain when touching the affected areas, which can be expressed by pulling away or whining.
Moist or weeping areas: Underneath the crusts, there may be weeping wounds or moist skin areas that indicate an active infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..
Behavioral changes: The dog may appear restless or irritable, indicating discomfort or pain.

When to visit the vet?

A visit to the veterinarian is necessary if the crust formation lasts longer than a few days or worsens. Also, if the dog shows signs of severe pain, excessive itching, or other systemic symptoms such as fever, a veterinarian should be consulted immediately.

If the crusts are accompanied by severe hair loss, persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. itching, or weeping wounds, this could indicate a serious infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or allergic reaction that requires professional treatment.

If a parasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., such as mange, is suspected, a quick visit to the veterinarian is crucial to prevent the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. from spreading to other animals or people.

Even if the dog has had skin problems in the past and the current symptoms differ from the usual patterns, a veterinarian should be consulted to clarify possible new causes.

Symptom recognition for animal owners and veterinary diagnostic procedures

Pet owners can recognize crusts in their dog by paying attention to skin changes, unusual scratching, or other behavioral changes. Regular checking of the coat and skin for abnormalities is important in order to intervene early.

The veterinarian will perform a thorough examination of the skin to determine the cause of the crusts. This includes a visual inspection as well as palpationPalpation is an examination method in which the condition of body tissues is assessed by feeling them with the hands. It is used to identify swelling, pain, or other abnormalities. of the affected areas to detect inflammation or pain.

In addition, diagnostic tests such as skin smears, biopsies, or blood tests may be necessary to identify infections, parasites, or allergic reactions. A skin smear can be examined for bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. or fungi, while a biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. can provide information about autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus..

In some cases, an allergy testAn allergy test is a method for the diagnosis of allergic reactions. The body is exposed to various allergens to identify which substances trigger an allergic reaction. may be necessary to rule out or confirm allergic reactions. This can be done through blood tests or skin tests.

What can pet owners do and professional therapy options

As a first measure, the pet owner should try to keep the affected area clean and dry to prevent the symptoms from worsening. Regularly cleaning the crusts with mild, lukewarm water can help to remove dirt and irritants.

Wearing a protective collar can prevent the dog from further scratching or biting, which promotes healing of the skin and prevents infections.

It is important not to administer any medications or ointments to the dog without veterinary consultation, as this could worsen the symptoms or triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. an allergic reaction.

In addition, care should be taken to ensure that the dog receives a balanced diet and does not consume any allergy-triggering foods in order to strengthen the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and avoid allergic reactions.

If possible, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. factors for the dog should be reduced, as stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can weaken the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and delay healing. A calm, stress-free habitat can contribute to recovery.

Outlook on current research

Current research is intensively investigating how crusts form on the skin of dogs and what they can reveal about the animal’s general health. One focus is on the microbial colonization of the skin. Researchers are analyzing the role of bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and fungi that naturally occur on the skin of dogs and how this microbiota is involved in the formation of crusts. It is believed that an imbalanceImbalance refers to an imbalance or disruption of normal function or composition in the body, which can lead to health problems. of these microorganisms can weaken the skin’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., leading to a higher susceptibility to infections and thus to crust formation.

Another area of research focuses on the genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. of dogs to skin problems, including crusts. Certain breeds show a higher susceptibility to skin diseases, and scientists are investigating the genetic markers associated with these problems. This research could help to better predict which dogs are at higher risk of developing crusts and to develop targeted preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies.

In addition, there are advances in the development of new diagnostic tools to better understand the causes of crusts in dogs. Novel imaging techniques and skin tests are being developed to analyze the structure of the skin and the composition of the crusts more precisely. In the future, these technologies could help to determine more quickly and accurately whether a bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., a fungal infestation, or an allergic reaction is present that leads to crust formation.

Another interesting aspect of the research is the investigation of the role of environmental factors. Studies show that factors such as nutrition, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., and environmental pollution can have a significant impact on the skin health of dogs. Researchers are working to understand the exact mechanisms by which these factors weaken the skin barrier and contribute to the development of crusts. These findings could help to provide recommendations for optimal housing and care of dogs that minimize the risk of skin problems.

With regard to the treatment of crusts in dogs, intensive research is being conducted into the development of new topicalTopical refers to the direct application of medications or treatments to the skin or mucous membranes for a local effect, without being absorbed into the body. and systemic therapies. There are promising approaches based on natural substances to promote skin healing and reduce inflammation. The development of personalized treatment plans based on the individual needs and specific skin condition of the dog is another exciting area of current research.

In summary, research shows that crust formation in dogs is a complex interplay of genetic, microbial, and environmental factors. The ongoing studies are helping to develop a deeper understanding of these processes and to find innovative approaches to prevent and treat skin problems in dogs. The results could not only improve the quality of life of pets but also provide valuable insights for human dermatologyDermatology is the branch of medicine that deals with the structure, function, and diseases of the skin. It includes the diagnosis and treatment of skin, hair, and nail disorders..

Frequently asked questions

What are the most common causes of crusts in dogs? Crusts can be caused by a variety of factors, including bacterial infections, fungal infections, allergies, parasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. infestations such as fleas or mites, and skin injuries. Each of these causes can lead to inflammation or infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. of the skin, which in turn leads to the formation of crusts. A visit to the veterinarian is often necessary to determine the exact cause.
Can I treat crusts on my dog myself? While it is possible to treat minor skin injuries at home, you should definitely consult a veterinarian for persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. or severe crusts. Self-diagnosis can be difficult because the cause of the crusts can be varied. A veterinarian can make an accurate diagnosis and recommend the right treatment to avoid complications.
Are crusts painful for dogs? Crusts can be painful, especially if they are accompanied by inflammation or infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Your dog may show signs of discomfort, such as frequent scratching or licking of the affected area, which can often worsen the situation. If you suspect pain, you should consult a veterinarian.
Can crusts be a sign of a serious illness? Yes, in some cases, crusts can be a symptom of serious illnesses, such as autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus. or systemic infections. If the crusts do not heal within a few days or are accompanied by other symptoms such as fever or lethargy, an immediate visit to the veterinarian is advisable.
How can I prevent my dog from developing crusts? Good skin care and hygiene are crucial. Regular brushing, a balanced diet, and avoiding allergens can help to avoid skin problems. In addition, you should pay attention to appropriate parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. prophylaxisProphylaxis refers to preventive measures taken to avoid diseases or health problems. In veterinary medicine, this can include vaccinations, regular deworming, and other preventive treatments. and check your dog regularly for fleas and mites.
What home remedies can help with the treatment of crusts? Some home remedies, such as diluted apple cider vinegar or aloe vera gel, can be helpful in treating minor skin problems. However, it is important to use these remedies with caution and ensure that they are safe for dogs. If you are unsure, it is better to consult a veterinarian.
Should I scratch off or remove the crusts? It is not recommended to forcibly remove crusts, as this can lead to further injuries or infections. Allow crusts to fall off on their own or consult a veterinarian for appropriate treatment that supports the healing process.
How long does it take for crusts to heal in dogs? The healing time can vary depending on the cause and severity of the crusts. Smaller, uncomplicated crusts can heal within a few days, while more severe cases or those that are accompanied by an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. can take weeks. Appropriate treatment can accelerate the healing process.
Can crusts in dogs be transmitted from person to person? In most cases, crusts in dogs are not contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. to humans. However, there are certain skin diseases, such as ringworm, that are zoonotic and can be transmitted to humans. Caution is advised if a contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. disease is suspected and a veterinary examination is advisable.
How can I tell if the crusts on my dog are getting better? An improvement is often shown by a reduction in redness, swelling, and itching around the affected areas. In addition, the crusts should gradually heal and the skin underneath should look healthy. Regular check-ups with the veterinarian can also help to monitor the healing process.