고양이 피부사상균(링웜)과 기생충 감별 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

Feline Dermatophytosis (Ringworm) vs. Parasitic Infections: Frequently Asked Questions — Key Points for Pet Owners

Infection/ParasitesQ&AMeongsiljang Veterinary Advisory Board

Among feline skin issues, dermatophytosis (ringworm) and parasitic infections can present similar symptoms, making them easy to confuse. Learn how to accurately distinguish between them and the appropriate steps to take.

Distinguishing Feline Dermatophytosis (Ringworm) from Parasitic Infections: 5 Key Questions

A cat with circular patches of hair loss on its face and legs.

Feline ringworm (dermatophytosis) and parasitic infections can cause similar skin symptoms, making it easy for pet owners to confuse the two. - Ringworm (Dermatophytosis): Hair loss is common, often accompanied by scaling (dander), crusts, and broken hairs. Although commonly referred to as "ring" shaped, the actual lesions can vary widely in appearance and may present as localized, multifocal, or generalized. Itching is usually mild or absent. Lesions frequently appear on the muzzle, ears (pinnae), around the eyes, legs, toes, and tail. - Parasitic Infections: Flea or tick infestations, in particular, cause intense itching, leading cats to lick or scratch frequently. Lesions commonly occur on the back (especially the lower back near the tail), abdomen, hind legs, flanks, and neck. Veterinary examination is essential for an accurate diagnosis. Early detection and treatment are key to successful outcomes.

Why Is It Easy to Confuse Dermatophytosis with Parasitic Infections?

Both dermatophyte infections and parasitic infestations cause hair loss, itching, and skin scaling or crusting, making them difficult to distinguish in the early stages. - Dermatophytes (ringworm): Hair loss is commonly accompanied by scaling, crusting, and broken hairs. Lesion shapes vary widely and are not always circular; chronic cases may lead to thickened or hyperpigmented skin. Itching is usually mild or absent. - Parasitic infestations: Flea or tick infestations often cause intense itching, leading cats to lick or scratch frequently. Lesions tend to be irregular in shape and can spread over large areas. Both conditions are contagious and can spread to other pets. Except for Demodex (Demodex mites), external parasites and dermatophytes can also be transmitted to humans. Accurate diagnosis by a veterinarian is essential.

An image comparing a cat’s ringworm lesion with skin affected by parasitic infection

What Are the Main Characteristics of Dermatophytosis (Ringworm)?

Dermatophytosis (ringworm): Hair loss is the primary symptom, often accompanied by scaling (dandruff), crusts, and broken hairs. Lesions vary greatly in appearance and are not always circular; they can spread locally, appear in multiple spots, or become generalized. The most commonly affected areas are the muzzle, around the eyes, ear flaps, legs (especially the front legs), toes, and tail. In chronic cases, the skin may thicken or become hyperpigmented. Itching is usually mild or absent, though severe facial pruritus can rarely occur. This zoonotic infection is highly contagious and can be transmitted to humans, making early diagnosis and treatment essential. Pay particular attention to the face, ears, and interdigital spaces (between the toes) in the early stages.

A cat with multiple circular patches of hair loss on its face and legs.

What Are the Main Symptoms of Parasitic Infections?

Parasitic infections: Flea or tick infestations often cause intense itching. Cats may frequently lick or scratch, leading to small, pimple-like rashes (miliary dermatitis) or scabs from skin abrasions. Lesions commonly appear on the lower back near the tail base, but can also occur on the belly, hind legs, sides, and neck. Demodex (follicle mite) infections typically affect the areas around the eyes, head, neck, and ears, with varying degrees of itching. These lesions tend to be irregular rather than circular and can spread over a wide area. Early detection and treatment are essential.

A cat scratching its ears, with red and irritated skin.

Dermatophytosis vs. Parasitic Infections: Key Comparison Table

Item	Dermatophytosis (Ringworm)	Parasitic Infection
Main Lesion Form	Varies (not always circular), accompanied by scales, crusts, and broken hairs	Irregular shape
Degree of Itching	Mild or absent (rarely severe facial itching)	Very severe
Main Affected Areas	Muzzle, around the eyes, ear pinnae, legs, toes, tail	Lower back (rump/back near the tail), belly, hind legs, flanks, neck
Contagiousness	High (zoonotic, including to humans)	Often transmitted between animals, but external parasites other than Demodex can also be transmitted to humans
Diagnostic Methods	Fungal culture, PCR, direct microscopic examination, Wood's lamp examination (partially helpful)	Skin scraping, flea examination, tape test, hair collection

An accurate diagnosis requires an examination by a veterinarian. Self-diagnosis is dangerous.

What Tests Are Needed for an Accurate Diagnosis?

- Dermatophytosis (Ringworm): The gold standard for diagnosis is a fungal culture of skin or hair samples. Additionally, skin scrapings or hair can be examined directly under a microscope or tested using PCR. In some cases, a Wood’s lamp examination may reveal an apple-green fluorescence, which suggests a possible *Microsporum canis* infection. However, a Wood’s lamp alone is insufficient for a definitive diagnosis, so confirmation through culture or other methods is essential. - Parasitic Infections: These are diagnosed through skin scrapings, flea tests, or tape tests. A veterinarian must perform and examine these tests to ensure accurate results. Early diagnosis is key to successful treatment.

A veterinarian examining a cat's skin with a Wood's lamp

Signs That Require an Immediate Vet Visit

If your cat is scratching or licking excessively, causing the skin to peel, or if the affected area is rapidly expanding or other animals have been infected, you should visit the vet immediately. Early diagnosis and treatment are crucial, especially since humans can also become infected.

What Are the Differences in Treatment Methods?

- Dermatophytosis (Ringworm): Treatment involves a combination of oral antifungal medication and topical applications. For cats, itraconazole is the approved systemic antifungal, and it is recommended to supplement this with topical treatments once or twice a week. Do not discontinue medication prematurely; continue administration until both clinical symptoms resolve and fungal culture tests return negative, a process that typically takes several weeks. - Parasitic Infections: Use flea and tick control products, which are available in various forms such as topical solutions, oral medications, and collars. For both conditions, thorough environmental cleaning is essential during treatment. Be sure to clean and manage household items like beds, carpets, and toys. Early treatment is key to preventing reinfection.

A cat receiving a topical antifungal medication

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

My cat has started losing hair. How can I tell if it’s ringworm or parasites?

An accurate diagnosis requires a veterinary examination. Since it is difficult to distinguish conditions based on symptoms alone, we strongly recommend visiting a clinic. Dermatophytosis is confirmed through culture or PCR testing, while parasitic infections are identified via skin scraping, flea checks, and other diagnostic methods.

Can ringworm be transmitted to humans?

Yes, dermatophytes can also be transmitted to humans. Extra caution is especially important for children and individuals with weakened immune systems. If infection is suspected, it is important for the person to visit a nearby medical facility, such as a dermatology clinic, for evaluation.

Can parasitic infections recur even after treatment?

Yes, if the environment isn’t properly cleaned, reinfection can occur. It’s important to thoroughly clean and maintain your entire home, and also be cautious about contact with other animals.

Is it safe for my cat to come into contact with other animals while undergoing treatment?

No, it is highly contagious, so you should avoid contact with other animals during the treatment period. Even after treatment is complete, managing contact is necessary to prevent reinfection.

Can ringworm be prevented at home?

Yes, regular cleaning, limiting contact with other animals, and washing your hands after handling them can all help prevent infection. In particular, catteries and multi-cat households carry a higher risk, so extra attention to preventive care is essential.

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References

[1] Moriello KA (2019) Dermatophytosis in cats and dogs: A practical guide to diagnosis and treatment. /n Practice 41, 138-144.

[2] BSAVA Manual of Canine and Feline Dermatology, 4th Ed (2017). Chapter on Dermatophytosis.

[3] Clinical Medicine of the Dog and Cat, 4th Ed (2020). Dermatologic Disorders section.