Treatment of Ringworm

Treatment of Ringworm


"Positive DTM Ringworm Culture shows the fluffy white fungal colony turning the yellowmedium red as it grows."

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Confirm the diagnosis - recommended to do fungal culture in almost all dermatological casesbecause of the varied presentation - from classical expanding areas of scaling or erythema toPersian keratinisation defects (chronic infection) to military dermatitis, kerions, nodules andsymmetrical alopecia - it can look like ANYTHING!

- Wood's lamp (ultraviolet light) - miss 70% of cases, positive only suggestsdermatophytosis so must still do fungal assay to confirm. - Trichogram (infected vs normal hair shaft) - may still miss the diagnosis. - Skin biopsy - a good way to rule out mites, ringworm, eosinophilic/hypersensistivity andautoimmune differentials - don't biopsy heels, ears - biopsy is not the first step in a skinwork-up, but in cats we do it sooner than later especially since skin scrapings are not always anoption. Always biopsy before treating with steroids! - Fungal assay (DTM - dermatophyte culture assay; medium turns red on first white growth;will turn red anyway after approx. ten days; contaminants often green/black coloured) - Fungal culture and identification (send to CVL, takes about three weeks so if in-houseDTM is positive start topical treatment at least) - Collect samples using sterile/new toothbrush, sterile carpet, sterile tweezers - notcold-sterile because the germiphene residue will kill the sample.

ZOONOSIS - so topical treatment with systemic antifungals (mainstay remains bathingplus oral azoles) and environment (enilconazole weekly 4-8 times; bleach (chlorine) 1:10soln.)

Most healthy immune-competent cats will resolve the infection spontaneously over a fewmonths - however treatment is always recommended because this is contagious to humans and

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other animals. 8

1. Treat infected cat 2. Minimise spread of infection 3. Eliminate contamination of the environment

1. Treat infected cat

- Clipping the coat8 - remove infected hairs, minimise contagion - TOTAL BODY CLIP -optional in shorthairs with small localized lesions - destroy coat clippings and protective clothingimmediately - will contaminate environment where clipped so if clipping in veterinaryclinic/groomers MUST do rigourous environmental cleanup. - Systemic antifungal treatment8 - Griseofulvin, Ketoconazole, Itraconazole - Vaccination - will not cure, may prevent spread, no controlled studies yet that showprotection against natural or challenge exposure 8 - Topical therapy - useful for small localized lesions, but must prevent ingestion! - best isenilconazole or combination ketoconazole/chlorhexidine shampoos. 8 Have to doweekly/twice weekly 8-10 weeks. Topical creams or enilconazole solution topically daily alsocan have good result for small localized lesions - but remember you need to consider whole cat is infected, not just the raw patch yousee! - Monitor therapy methodically - cats will appear clinically normal long before they are curedmycologically (ie easy to stop treatment too soon) - spontaneous resolution 60-100 days,treated cats 28-56 days (4-8 weeks). Treat till fungal culture (done weekly, starting after 3-4weeks of therapy) is negative on two or three successive occasions. 8

2. Environmental Clean-Up

- Environment a reservoir of infection - Start with aggressive cleaning - wash everything that can be washed (bedding, toys,

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scratching posts, brushes, anything and everything) - in severe cases, destroy whatever cannotbe washed. Vacuum everything - all surfaces - ceilings, vents, floors, walls, anyplace where cathair or dust can accumulate is a source of infection. Then clean every surface you can with asafe detergent. Colonies/ catteries - Heating/Airconditioning systems need to be cleanedand then the filters changed, weekly, till free of infection. - Antifungals do not work in dirt - so now that the place is clean, apply antifungaldisinfectants - enilconazole 1:50 dilution spray or bleach 1:10 - this can be irritating so preventhuman/cat contact with these agents; catteries/colonies/vets/groomers need to do thisdaily/every other day for several months after cure - spores carried in air and resistant for a longtime!

3. Prevent spread to other animals and people

- Identification, isolation, quarantine, monitoring - applicable mainly to catteries/colonies -individually affected cats in households there is a good chance the owners have already beeninfected and are being treated. - Ringworm - cat to people but also people to cat! Identification of species can give you valuable clues as to the source of

Review Table of Specific Treatments.

Individual Cats

Rx

n

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Comment

Products

Lufeneron alone 3,4

Fails to prevent infection5,6

Program

Topical antifungal cream

For small localized lesions; prevent ingestion

Conofite

Clorhexidine

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For small localized lesions; also as part of shampoo; antifungal residual effect cumulative

Hibitane

Iodine

Potassium or sodium iodide as a tincture dabbed to the spot; oral or iv (KI 1g/35g max 2g po in pigs; NaI 10% soln 1g/14kg iv in cattle) NOT recommended!!! Vioform both antifungal&antibacterial, don't get in eyes; not generally recommended these days.7

Lugol's

Betadine

Vioform (iodochlorhydroxyquin 3%)

Antifungal shampoo

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Whole cat wet to the bone twice weekly (once weekly has also worked) for at least 8 treatments; suggest do in clinic; let sit wet and sudsy 5-10 mins; dry cat poperly to prevent matting or lion-shave long-haired cat; often combined with systemic antifungals

Nizoral (ketoconazole)

Imaverol (enilconazole)

Malaseb (miconazole plus chlorhexidine)

Systemic antifungals

Do not use in cats with liver disease; may see raise in liver enzymes during treatment â?? suggest get baseline values before starting treatment and monitor values 10d after starting treatment; the newer drugs have less side-effects but are more expensive

Griseofulvin

Sporanox (itraconazole)

With a fatty meal (normal cat food)

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Copper & Zinc sulphate

Farm remedy, 0.1-2% aq.solns, astringent, caustic-.would not recommend for a cat.7

Organic acids

Keratolytic activity - fungistatic, salicylic acid needs presence of water for effect, repeated applications cause irritation - would not recommend for a cat.7

Caprylic acid

Propionic acid

Undecylenic acid

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Benzoic acid

Salicylic acid

Combinations.

Sulphur

Miticidal ear prep 7

Lime sulfur dips?

Monosulfiram (tetmosol)

Captan

Carcinogenic, 1tbs/l water daily

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would not recommend for a cat 7

Tolnaftate

1%, can be administered with griseofulvin would not recommend for a cat 7

Dichlorophen

Taenicide, also effective topical fungicide, 2% ointments, tinctures; apply q 2-3days; bactericidal against staph.aureus.

would not recommend for a cat7

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Review Table of Specific Treatments and Studies.

Catteries, Multi-Cat Households Rx

n

Comment

lufeneron alone 3,4

Treatment failures at 50mg/kg, suggested min dose 100mg/kg repeated after 14d

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Fails to prevent infection5,6

lufeneron (60mg/kg po day 0 and day 30) plus enilconazole (0.2%) rinses weekly1

100

Fungal cultures

Mean number of fungal colonies decreased rapidly during first 15d rx, remained stable next 45d, then increased from d60 to d90 (end of study) Environment was treated with enilconazole weekly for first 30d. Lufeneron protocol worked better in the cattery with lower population density that managed to significantly decrease environmental contamination. Cure took weeks, some remained culture positive, no definite eradication achieved

griseofulvin (micronised 25mg/kg po bid 5 weeks) plus enilconazole (0.2%) rinses weekly1

Do not use in pregnant cats - griseofulvin is teratogenic,

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also toxic to Persians, Himalayans, Siamese, Abyssinians and FIV+ cats2

Terbinafine

No controlled studies done in catteries on these drugs

Ketoconazole

Itraconazole

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References:

- Guillot et al, Evaluation of the efficacy of oral lufenuron combined with topical enilconazolefor the management of dermatophytosis in catteries, Veterinary Record, (2002), 150, 714-718 - Scott et al, 2001 - Ben-Ziony , Arzi; Use of lufeneron for treating fungal infections of dogs and cats: 297cases (1997-1999); Journal of the American Veterinary Association, (2000), 217, 1510-1513 - Ben-Ziony, Arzi; Updated information for treatment of fungal infections in cats and dogs,Journal of the American Veterinary Association, (2001), 218, 1718 - DeMoriello, DeBoer et al; Efficacy of pre-treatment with lufeneron for the prevention ofmicrosporum canis infection in a cat challenge model ; AAVD/ACVD 2002 proceedings - DeMoriello, DeBoer, et al; Efficacy of pre-treatment with lufeneron for the prevention ofmicrosporum canis infection in a feline cohabitant-challenge model; AAVD/ACVD 2002proceedings - Notes from Onderstepoort, 1995 - Guaguere, Prelaud; A Practical Guide to Feline Dermatology; Merial 2002 infection.

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Treatment of Ringworm