Ringworm is caused by a group of fungal organisms—Microsporum canis, Trichophyton mentagrophytes, and Microsporum gypseum. It is highly contagious for people and other animals.

Clinical signs range from an inapparent carrier state to severe, including focal to diffuse alopecia (hair loss), classic circular alopecia, miliary dermatitis (multifocal small pustules and scabs), scales, erythema (reddened skin), hyperpigmentation, and pruritus (itching). Ringworm affects the hair, skin, and nails. When nail beds are infected, the nails may appear brittle and malformed and have crusts and scales around the base of the nail.

Infection may not result in clinical signs. An affected animal that does not show clinical signs may remain in this inapparent carrier state for a prolonged period of time; some animals never become symptomatic. Inapparent carriers can be contagious.

It is possible for people to get ringworm from their pets. However, most children contract ringworm from other children. It is also possible for your pet to get ringworm from you! If you notice a red, itching rash or circular lesions on your skin, consult your physician.

Unfortunately ringworm is not always easily diagnosed. It can mimic a myriad of other diseases. There are three diagnostic tests usually done to help diagnose ringworm.

Wood’s Lamp Exam—This test can be used as a screening tool, but false negative results are common. Not all fungal organisms will flouresce a bright apple green color at the base of the hairs.

Skin scraping—This test is performed primarily to rule out Demodectic mange or Scabies as a differential diagnosis. The hair shafts are also examined for presence of fungal hyphae; however, this test can produce false negative results.

Fungal Culture—This test is the best means of confirming a diagnosis. However, even with this test, false negatives may occur. This test may take two to four weeks for complete results.

Based upon the severity of the disease and circumstances, treatment may consist of multiple methods.

1. Isolate the pet from all animal contact.

2. Wash any parts of your body that has been in contact with your pet. Contact your physician if you are suspicious of infection.

3. It is recommended that you wash all of the pet’s bedding daily.

4. Contact the owners of any pets that may have been exposed to your pet, so that they may observe their pets for signs of infection.

( ) Recommend clip the hair coat on long haired cats. This will help prevent

environmental contamination. However, there are two potential complications:

1. Clipping is often associated with an exacerbation of clinical signs. 

2. Sometimes the hair coat will grow back a different color and texture.

( ) Shampoo and Dip with prescribed medication every ____ days for ______

treatments, or for 1-2 dips past complete hair regrowth.

1. Drench entire hair coat and let shampoo/dip stay on for 10 minutes.

2. Be careful not to get into the eyes.

3. Be sure to mix dip as directed.

4. Let drip dry or blow dry. Do not towel dry.

5. For cats with LymDip, place a buster collar around the neck until the dip has dried so that the cat will not ingest the dip.

( ) Give antibiotics as directed for Secondary Bacterial Infection.

( ) Apply ointment/lotion to affected areas of skin ___ times daily/weekly until complete hair regrowth has occurred. Do not get into eyes.

( ) Anti-fungal vaccinations: Your pet will need to come back for vaccination in 2 weeks and again 4 weeks later.

( ) Systemic Antifungal Therapy:

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( ) Give medication with a meal high in fat or tuna fish oil for better absorption.

( ) Potential side effects are bone marrow suppression, gastrointestinal upset, or neurological side effects.

( ) Recommend CBC in ______ days/weeks.

( ) Medication will need to be given for a minimum of 4-6 weeks or longer. DO NOT DISCONTINUE MEDICATION UNLESS DIRECTED TO DO SO BY YOUR VETERINARIAN.

( ) Environment: Environmental treatment (including fomites—anything that may carry the fungus) is very important.

1. Vacuum thoroughly and frequently to remove as much hair as possible. Effective vacuuming entails 10-15 minutes in a 10X10 room. Dispose of the vacuum bag afterwards, removing it from the house. 

2. Dilute bleach (1:10) is safe and effective.

3. Clean all furniture and bedding.

Note: This article is provided by Claws & Paws Veterinary Hospital® for informational purposes only.