Home » Diseases » In cats » Dermatophytosis with Microsporum Canis (Fungal Infection of the Skin with Microsporum Species, Ringworm)

Dermatophytosis with Microsporum Canis (Fungal Infection of the Skin with Microsporum Species, Ringworm) in cats

Occurrence: common
Location of illness: General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.

Definition

Dermatophytosis with Microsporum canis is a fungal 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, often referred to as ringworm. It primarily affects cats and is characterized by circular skin lesions.

The most important facts at a glance

Dermatophytosis in cats, caused by the fungus Microsporum canis, is a common skin 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. that affects keratinized tissue such as skin, hair, and nails. The fungus is often transmitted through direct contact with infected animals or contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. objects. Risk factors include a weakened 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., poor hygiene, and 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., with young animals and older cats being particularly susceptible. Symptoms include round, thickened skin areas, scaling, itching, and hair loss. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through clinical examinations and laboratory tests such as Wood’s lamp examination and microscopic analyses. Treatment includes 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 antifungals that must be applied over an extended period. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good with early treatment, but 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. can become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. without treatment. Preventive measures include household hygiene, isolation of infected cats, and regular veterinary checkups. Research is focused on improved diagnostic methods, new treatment forms, and the development of vaccines. Epidemiological studies are examining how environmental factors and genetic differences influence the risk of 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.. These research approaches could improve cat health and reduce the risk for humans.

Causes

Dermatophytoses are fungal infections caused by dermatophytes. These fungi feed on keratin, a proteinProteins are large molecules made up of amino acids and play an essential role in almost all biological processes. They are necessary for building body tissue, the function of the immune system, and as enzymes for metabolic reactions. found in skin, hair, and nails. Microsporum canis is one of the most common pathogens of these infections in cats.

The fungus Microsporum canis belongs to the group of dermatophytes that specifically target keratinized tissue. These fungi can be transmitted through direct contact with infected animals or contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. objects. Cats are particularly susceptible because they regularly come into contact with their environment and other animals.

Factors such as a weakened 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., poor hygiene, or 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 increase the risk of 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.. Young animals and older cats are particularly at risk because their 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. is either not yet fully developed or weakened.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The most common symptoms of dermatophytosis with Microsporum canis include round, bald patches on the skin. These lesions may be accompanied by scaling, redness, and sometimes crusts.

The affected areas typically itch, causing the cat to scratch or lick, which can worsen 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.. In some cases, a secondary 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. may occur, causing additional skin problems.

Sometimes the cat shows only minimal or no symptoms, making it difficult to detect 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. early. This is particularly problematic because the disease is highly contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. and can easily be transmitted to other animals and humans.

Diagnosis

DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of dermatophytosis is typically made through a combination of clinical examinations and laboratory tests. A commonly used test is the examination of skin and hair under a special Wood’s lamp, which causes affected areas to fluoresce.

Another method is microscopic examination of hair and skin scales to identify fungal spores. These samples can also be cultured on a special growth medium to confirm the presence of Microsporum canis.

In some cases, a skin 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. may also be performed to rule out other skin diseases and confirm the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. An accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is important to initiate the right treatment and prevent the spread of 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..

Therapy

Treatment of dermatophytosis with Microsporum canis typically includes both 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 antifungals. 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. treatments involve applying antifungalAntifungal means effective against fungal infections. Antifungal medications are used to treat infections caused by fungi by inhibiting their growth or reproduction, or by killing them. creams, ointments, or shampoos directly to the affected skin areas.

Systemic antifungals, taken orally, are often necessary to completely combat 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., especially if it is widespread or does not respond to treatment with 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. agents.

It is important to continue treatment over an extended period, even if symptoms disappear, as the fungus can remain in the deeper layers of the skin. Additionally, the cat’s environment can be disinfected to prevent reinfectionReinfection refers to the recurrence of an infection in an individual who was previously cured of the same disease. This can be caused by the same or a similar pathogen..

Prognosis and follow-up care

The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for cats with dermatophytosis is generally good, provided 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. is diagnosed early and treated appropriately. Most cats recover completely within a few weeks to months.

Without treatment, however, 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. can become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. and lead to long-lasting skin problems. There is also the risk of transmission to other animals and humans, which underscores the importance of rapid and effective treatment.

Regular veterinary check-ups are important to monitor the progress of the treatment and ensure that 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. is completely controlled.

Prevention

To minimize the risk of dermatophytosis 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. in cats, it is important to perform regular hygiene measures in the household. This includes frequently washing cat beds, blankets, and other textiles that come into contact with the cat in hot water. Vacuuming can also help remove skin scales and fungal spores.

Isolating infected cats from other pets in the household is an important measure to prevent the spread of the fungus. In households with multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. animals, regular veterinary checkups should be conducted to detect and treat infections early.

It is advisable not to let cats roam outdoors unsupervised, as they can more easily become infected with Microsporum canis there. Especially young cats and those with a weakened 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. should be kept away from potential sources of 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..

Regular examinations and good general health care are also crucial to strengthen the cat’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.. A balanced diet and 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. avoidance help support the cat’s defenses.

Avoid contact with infected animals and ensure that new cats are examined by a veterinarian before being integrated into the household. Thorough cleaning of the environment and adherence to the mentioned measures can significantly reduce the risk of 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..

Outlook on current research

Dermatophytosis, particularly caused by the pathogenA pathogen is a microorganism or virus that can cause disease in its host. Pathogens include bacteria, viruses, fungi, and parasites. Microsporum canis, represents a common skin disease in cats that is significant for both the affected animals and their owners. Research is currently focused on several key areas. There is great interest in improving diagnostic methods. Traditionally, diagnostic procedures such as culture on special growth media and microscopic examination of skin samples have been used. However, newer research aims to further develop molecular techniques such as polymerase chain reaction (PCR) to enable faster and more accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..

Another major area of research focuses on developing more effective treatment methods. While traditional antifungals such as itraconazole and griseofulvin continue to be used, there are efforts to develop new medications that have fewer side effects and require a shorter treatment duration. Additionally, research is being conducted on vaccines that could work preventively to prevent new infections or mitigate the course of disease in already infected animals.

Another research area is the investigation of epidemiological factors that contribute to the spread of Microsporum canis. Studies are examining how environmental factors, cat behavior, and interaction with other animals and humans influence the risk of 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.. This helps develop effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies.

Finally, research is also examining how genetic differences between cats affect their susceptibility to Microsporum canis. Some studies suggest that certain cat breeds or individual genetic variants may have higher or lower susceptibility to infections. These findings could influence breeding strategies and the management of cat populations in the future.

Overall, current research shows promising approaches to improving the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients., treatment, and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of Microsporum canis infections. The results of these studies could not only improve the welfare of affected animals but also reduce the risk for humans who interact with cats.

Frequently asked questions (FAQs)

How do cats get infected with Microsporum canis? Cats typically become infected through direct contact with infected animals or contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. objects. The fungus can be transmitted from skin scales or hair containing the infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. material.
What symptoms does a cat with Microsporum canis show? Typical symptoms are circular, hairless patches on the skin that are often reddened and scaly. Itching may also occur but is not always present. Symptoms can vary depending on the severity of 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. and the cat’s 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..
Can humans be infected with Microsporum canis? Yes, Microsporum canis is zoonotic, meaning it can be transmitted from animals to humans. Humans, especially children or immunocompromised individuals, can develop ringworm upon contact with infected cats.
How is Microsporum canis diagnosed? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is usually made through a combination of methods, including examination under a special lamp (Wood’s lamp), microscopic examination of skin samples, and culturing the fungus in a laboratory. Modern methods such as PCR are increasingly being used to speed up diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..
What treatment options are available for infected cats? Treatment often includes the application of 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. antifungals, systemic medications such as itraconazole, and regular cleaning and disinfection of the environment. In severe cases, a combination of these methods may be necessary to completely eliminate 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..
How long does the treatment of a Microsporum canis 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. take? Treatment duration can vary but often ranges from several weeks to months. It is important to continue treatment until no signs of the fungus are detectable to prevent relapses.
Are there ways to prevent 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. with Microsporum canis? Preventive measures include limiting contact with infected animals, regular cleaning and disinfection of the environment, and maintaining good hygiene. In some cases, vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases. could be a future option if appropriate vaccines are developed.
Can all cats get Microsporum canis? Yes, in principle all cats can become infected, but factors such as age, health status, and 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. can influence susceptibility. Young animals and immunocompromised cats are particularly at risk.
What should I do if my cat shows symptoms of a Microsporum canis 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.? If you notice symptoms in your cat, you should immediately consult a veterinarian to obtain an accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and begin appropriate treatment. Early intervention can reduce the duration and severity of 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..
Can my cat fully recover after a Microsporum canis 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.? Yes, with proper treatment, cats can usually recover completely. It is important to carry out treatment exactly as recommended by the veterinarian and to conduct regular follow-up examinations to ensure that 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. is completely eliminated.

Frequently asked questions (FAQs)

1. How do cats get infected with Microsporum canis?

Cats typically become infected through direct contact with infected animals or contaminated objects. The fungus can be transmitted from skin scales or hair containing the infectious material.

2. What symptoms does a cat with Microsporum canis show?

Typical symptoms are circular, hairless patches on the skin that are often reddened and scaly. Itching may also occur but is not always present. Symptoms can vary depending on the severity of the infection and the cat's immune response.

3. Can humans be infected with Microsporum canis?

Yes, Microsporum canis is zoonotic, meaning it can be transmitted from animals to humans. Humans, especially children or immunocompromised individuals, can develop ringworm upon contact with infected cats.

4. How is Microsporum canis diagnosed?

Diagnosis is usually made through a combination of methods, including examination under a special lamp (Wood's lamp), microscopic examination of skin samples, and culturing the fungus in a laboratory. Modern methods such as PCR are increasingly being used to speed up diagnosis.

5. What treatment options are available for infected cats?

Treatment often includes the application of topical antifungals, systemic medications such as itraconazole, and regular cleaning and disinfection of the environment. In severe cases, a combination of these methods may be necessary to completely eliminate the infection.

6. How long does the treatment of a Microsporum canis infection take?

Treatment duration can vary but often ranges from several weeks to months. It is important to continue treatment until no signs of the fungus are detectable to prevent relapses.

7. Are there ways to prevent infection with Microsporum canis?

Preventive measures include limiting contact with infected animals, regular cleaning and disinfection of the environment, and maintaining good hygiene. In some cases, vaccination could be a future option if appropriate vaccines are developed.

8. Can all cats get Microsporum canis?

Yes, in principle all cats can become infected, but factors such as age, health status, and genetic predisposition can influence susceptibility. Young animals and immunocompromised cats are particularly at risk.

9. What should I do if my cat shows symptoms of a Microsporum canis infection?

If you notice symptoms in your cat, you should immediately consult a veterinarian to obtain an accurate diagnosis and begin appropriate treatment. Early intervention can reduce the duration and severity of the infection.

10. Can my cat fully recover after a Microsporum canis infection?

Yes, with proper treatment, cats can usually recover completely. It is important to carry out treatment exactly as recommended by the veterinarian and to conduct regular follow-up examinations to ensure that the infection is completely eliminated.