Infectious - Ringworm


Infectious - Ringworm

Lufenuron (Program Rx) for treating a cat with ringworm

Question: Dr. Mike- I have heard that I can treat my cat for ringworm using Program. Is this true?

Answer: L- Ringworm (dermatophytosis) can be treated with lufenuron (Program Rx). Dr Ziony's recommendations are as follows: Thank you for quoting my research (JAVMA publication, Nov 15, 2000) in your answers regarding the use of lufenuron for the treatment of fungal infections of dogs and cats. I would like to update you on certain innovations which I had the privilege to present at the Boston AAHA Annual meeting on March 26, 2002. Based on additional clinical experience the recommended dosages of lufenuron are as follows: Cats and dogs: 80-100 mg/kg Cats in catteries: at least 100 mg/kg The treatment should be repeated once every two weeks until at least two consecutive fungal cultures are negative over a period of two weeks. In our JAVMA publication we reported on a mycological treatment study based o 23 cats and 16 dogs (a total of 39 animals). In addition 297 lufenuron-treated animals were included in the clinical study. The new data is based on the mycological examination of 59 cats and 47 dogs (a total of 106 animals). Cats (59). These were 56 cases of M. canis, 2 cases of T.mentagrophytes and one case of M. gypseum. Dogs (47). These included 28 cases of M.canis, 14 cases of M. gypseum and 5 cases of T.mentagrophytes. In JAVMA we reported mean recovery times of 8.3 days for cats and 14.5 for dogs. In the new study the range of recovery times for cats with M. canis and M. Gypseun is from 6 to 37 days with a mean of 13.7 days. For dogs the new values are 6 to 32 days with a mean of 16.7 days for M. canis and M. gypseum. For cases of T. mentagrophytes recovery takes a little longer: 16 days for cats and 18 for dogs. These times are based on the time taken for daily fungal cultures to be negative and remain negative for 6 to 8 weeks. times are based on the time taken for daily fungal cultures to be negative and remain negative for 6 to 8 weeks. Dr. Yair Ben Ziony DVM, (Also in the name of Dr. Boaz Arzi, DVM, and second Author of our JAVMA publication) This is not an approved use for lufenuron in the United States. However, the other commonly used medication is itraconazole and it isn't approved for use in cats, either. At this time it seems apparent that lufenuron does not work in all cases of ringworm in cats even at the higher dosage. However, it does appear to be a relatively safe treatment for the condition and the ease of use is also a benefit. Lufenuron can also be used in dogs at the same dosages. Mike Richards, DVM 3/1/2002

Ringworm treatments

Question: Dear Dr. Mike, My cat is a ringworm sufferer. No longer have I cured her when it flares up again. I know I am doing everything humanly possible but to no avail. I used Grisofulvin daily for one month which did help but made her lifeless - I've also tried other internal medicines and anti-bacterial shampoos and I'm presently using a fungal spot treatment which I put on the hot spots daily for 3 days then another bath. It contains DI water, triclosan, d-alpha-tocopherol, mix tocopherol and vegetable oil. She is now pregnant and has broken out everywhere. Is it safe to continue this treatment or should I stop (she is not taking internal medicine). How can I stop the kittens from getting this disease if the mother has it chronically? I have other cats at home and afraid that they are all going to get this. If there is no cure for her would it be unreasonable to put her to sleep to save the others from catching it - I'm in a dilemma. Any advice would be greatly appreciated. Thanks. G.J.

Answer: G.J.- The problem with griseofulvin is that it is a fungiostatic medication, which means that it suppresses the infection but is unable to kill the fungus. This means that the cat's immune system must provide the killing effect. Some cats aren't capable of helping the griseofulvin work, so the treatment fails. There are two alternative medications to consider in cats that do not respond to griseofulvin. The first is itraconazole (Sporanox Rx), which is used at a dose of 10mg/kg/day for 15 days. If necessary, the medication may be repeated. Itraconazole can cause liver problems and it is a good idea to watch carefully for any signs of depression or inappetance when using this medication and to run appropriate lab tests if they occur. Itraconazole worked well for about half the cats which were not responsive to griseofulvin, in one published study. The second alternative is terbinafine (Lamisil Rx). There is a study in which 15 cats were treated with this medication (Francesca Mancianti, 1999) and 12 did well. These were not cats who had not responded to griseofulvin, though. The dosage used in the study was 30mg/kg/day for two weeks. These studies followed cats infected with Microsporum canis, the most common form of ringworm. Some cats are infected with Trichophyton species of ringworm. It is reasonable to assume the medications would work for these species of ringworm, as well, but I am not sure the same dosages and treatment durations would work. It is necessary to use oral medications to cure cats chronically infected with ringworm. It is also important to get the spores out of the environment since susceptible cats can get reinfected. Cats can carry this infection without any visible signs of infection so it may be best to treat all the cats. Vacuuming the house daily, changing the vacuum bag each time, is helpful. Cleaning any surfaces you can with dilute chlorine bleach solution would be a good idea using 1 part chlorine bleach and 30 parts water. I hope that the newer antifungal agents will work for you. Mike Richards, DVM 7/30/2000


Question: Dear Dr Mike, Our 7 month old cat endured severe ear mite infestation at age 4 months and this has finally been eradicated with his vet confirming the ears now completely free of mites. We also followed through with monthly flea treatment to avoid mites living on the rest of the body. However during the last 3 months the cat has been experiencing itchy ears and scratching around the head - it now turns out that he was also suffering from ringworm (no lesions visibile at the time). The ringworm lesions are very clearly showing up now covering the ears, all over the face (including nose and corners of eyes) and also signs of hairs thinning on lower back and tail. The vet has confirmed ringworm and is treating the cat with oral medication (Grisovin 125mg daily). The eyes were also treated for conjunctivitis and for the past month the third eyelid on the left eye has been constantly visible (across half the eyeball). We would like your opinion on - 1. How long the ringworm lesions usually last? 2. How infectious this is (my husband has had one lesion 2 months ago and I've had 2 bouts of Impetigo - any link?) 3. What do think of the third eyelid problem? 4. The cat's breeder suggested topical use of Myzorol 2% in addition to oral medication to assist with clearing ringworm up - is this necessary? We would be very grateful for your advice as we have had our little kitten for 4 months now and we really have yet to see him at his best - he has had so much to deal with and deserves a break! Regards, S. (Australia)

Answer: S.- Ringworm infections are often self-limiting, clearing up in 6 to 8 weeks whether they are treated, or not. But this is not always the case and there are cats who have very persistent problems with ringworm. In addition, many of the cats who no longer have ringworm lesions are still carriers of the disease. For this reason, we favor treatment of cats when we grow ringworm organisms from cultures. It would not surprise me if the infections that both you and your husband had came from contact with your cat. Ringworm is considered to be a zoonotic disease, or one that can be transferred from pets to humans. The ringworm most commonly carried by cats is Microsporum canis. There are other ringworm infections that come from the soil. In the case of one of these infections it is more likely that everyone was exposed to the same source, rather than a transfer of the infection from the cat to the human members of the family. It is usually recommended to continue systemic therapy with griseofulvin for six to eight weeks in order to eliminate the infection. It is probably best to do a "toothbrush" culture at the end of this treatment period to make sure the organism is gone from your cat's skin. To do this, a new toothbrush is used to brush a wide area of the haircoat and then the bristles are cultured for the ringworm organism. Your vet will be able to find instructions for this, if he or she doesn't already do this type of culturing. Griseofulvin limits the contagiousness of the ringworm organism pretty rapidly but using a miconazole shampoo might help some in limiting spread of the organism. There isn't much evidence that topical treatments are effective, so do rely on the oral medication for the treatment of the ringworm. Vacuuming the house daily (I know, a real drag) and changing the vacuum cleaner bag after each cleaning is supposed to be the most helpful thing for eliminating the fungal spores from the household. Cleaning any surfaces that can be cleaned with dilute chlorine bleach solution 1:10 is also supposed to be helpful. The third eyelid lesion could be Horner's syndrome. This is a sympathetic nervous system disorder that is not too uncommon in cats. Usually the pupils appear to be different sized, as well. If this is the case, the pupil in the eye with the visible third eyelid should be smaller than the one on the other side (which is actually the normal sized one). This condition can occur spontaneously in cats and will often resolve spontaneously, too. If not, chest X-rays may be advisable since masses in the chest are one possible cause of this condition. Good luck with all of this. Mike Richards, DVM 10/22/99

Fighting ringworm

Q: For the second time in the last year, I am fostering a litter of kittens that have ringworm.....With the last outbreak, I learned a great deal about fighting this fungus. In addition to the usual weapons in the arsenal (frequent vacuuming, baths, using gloves, internal medicine), etc....I have tried a new trick that I believe helps contain the spread of the fungus from the "foster children" to myself, my husband and my own pets. When I found that the anti-fungal medicines like Lotrimin and Tinactin came in spray cans, I started using it on all those areas that one is afraid to use bleach myself and my clothes after coming out of the room where the kittens are housed, on furniture, door knobs, etc....what I need to know is how effective do you believe this might be? Does anti-fungal mean that the medicine kills the fungus on contact like a bleach? The containers claim that it "cures" ringworm.....I guess that this method might help me contain the spread, but I'm looking for some- one "in the know" that could tell me if this is just wasted time and money. Thanks for listening.. R

A: R- I have not seen data on the use of Lotrimin (Rx) or Tinactin (Rx) in the manner you describe. To the best of my knowledge nothing kills the spores of the fungal agents that cause ringworm except maybe steam cleaning (that might hurt if you're trying to clean yourself). But I am not sure that this wouldn't be a reasonable way to prevent the spread of the organism to yourself from fungal elements other than spores. I am not sure how to check on this information. If I can figure out a way to research this I will try to remember to respond again. Mike Richards, DVM


Q: Dear Dr. Mike, My husband and I are new cat owners. I bought two siamese kittens at four months old in April this year. (They are brother and sister). We don't have children in the house and I am pretty much a clean freak. Two weeks after I brought them home from the breeder, I got an oval lesion on my torso. I thought it might be a stress related disease because I am a high strung person. (I'm working on that)... Within a week about a dozen of these sores spread to other parts of my body; arms and legs, none of them any larger than a dime. I made an appt. with a Dermatologist and a Vet. The cats had received their first immunization at the breeders and have continued the series at the vets. The MD did a scrape biopsy and a shave biopsy and determined a non-specific dermatophyte and gave me Spectazol cream, econazole nitrate 1%. The Vet's Woods lamp did not fluoresce on the male but did very slightly on the female, the tip of her nose and one of her titers. They both were dipped and we were sent home with instructions to disinfect the house with chlorhexiderm and I treated her two infected sites with OTC Lotrimin AF cream. They have also been declawed and fixed as they are strictly indoor cats. O.K. so this was in June and the female cat lost a patch of hair about a month and a half ago. Two weeks later, I got another sore on my leg. It was just one, and the Spectazole probably kept it form spreading. I also treated her patch, about the size of a dime, on her back, with a drop of iodine and the same cream I am using. We went back to the vets yesterday because I am very concerned that I can't stop the cycle of this fungus. She ordered the ringworm vaccination and we will start the series of shots in three weeks. Meanwhile they will be bathed in a 2.5% Benzyol peroxide shampoo one every 10 days and sprayed twice a day with a mild solution of the chlorhexiderm. My question is this: Could the cats have gotten ringworm from my husband, he has an athletes foot condition. He treats his flare ups with Clotrimazole 1%very conscientiously. The odd thing is that he wasn't even home when I got the first lesion, he was gone for six weeks. Could the cats have contracted it from the bottom of the bathtub, they like to jump in and lick the water. Why, I don't know. Since then I pored chlorine bleach into the tub and let it sit for a contact time of ten minutes, filled up the tub and ran it through the jets. I constantly use chlorine bleach in washing our bed sheets and towels, his socks and underwear, dish towels, hand and bath towels. ( I told you I was a clean nut.) I am a licensed esthetician ( a skin care professional ) and would like to start work in my field, but and concerned with just how communicable this fungus is? Do you think that the ringworm vaccine will work for the cats? Please let me know what you think, and thank you for reading this long drawn out story. Sincerely, Dave and Elsie in San Diego

A: Dave and Elsie- I can't say for sure, obviously, but I would say that the odds are best that the kittens have ringworm (a dermatophyte) and that you acquired it from them. Dave probably has an entirely unrelated problem and did not infect the cats or acquire his infection from them. I think that most cats with confirmed ringworm infections should be on oral medications to control the condition. Griseofulvin is still our favorite, but the newer anti-fungal agents like itraconazole can be used if desired. The "vaccine" for ringworm suppresses the symptoms but does not stop the contagiousness of the ringworm to you or to other cats. This is good for the kitten but falls short of what you are hoping for. Fortunately, ringworm infections usually clear up on their own, with or without treatment so there is a good chance things are OK now. If you continue to be bothered by the ringworm or if the cats appear to be, it would be best to check them to be sure one is not a carrier. Sometimes after infection the ringworm organism will live on the cat without causing clinical signs. The cat is still infective to a human or other cat, though. To determine this a "toothbrush" culture is a good idea. By running a sterile toothbrush through the fur of the cat and then culturing from the bristles, it is often possible to find inapparent ringworm infections in cats. Treating the household environment is best done by thorough and repeated vacuuming. Throw the vacuum cleaner bag away after each vacuuming and do this once a day for a week or more. Surfaces that can be treated with chlorine bleach diluted 1:10 may be disinfected in that manner. I am not a physician and can't comment too much on Dave's problem but one thing to consider is that most antifungal creams need to be applied for several weeks AFTER the clinical signs of infection disappear. It might be something to discuss with the doctor. Mike Richards, DVM


Q: Hello, My daughter recently got ringworm on her arm. I have a cat and I don't see any type of skin problem with the cat. Can you tell me what to look for? I have had the cat for 3 weeks now and nothing like this has ever happened before. Please Help.

A: M-Some cats can carry the ringworm fungus without any apparent sign of illness at all. The best way to find out if your cat is infected is to ask your vet to do a "toothbrush" culture. In this test a sterile toothbrush is used to brush the cat's hair over a wide area and then the bristles are pressed on the surface of a special culture medium for dermatopyhtes (the ringworm organism). Dermatophyte infection can be picked up from the environment as well as from cats but it does seem suspicious that you just got the cat and your daughter has a new ringworm infection. It would be best to have your cat checked for this. Mike Richards, DVM

Ringworm treatment

Q: My cat has ringworm on her ear. The Vet has him on Fulvicin and Conofite drops. A friend told me to stop the Fulvicin, that it can cause serious liver damage and to use Grecian Violet and it would clear up right there any truth to this? I have been using the drops for 2 weeks and the Fulvicin a week...I have noticed barely any changes. How long does it take to clear up? I sleep with my cat so.....I am anxious for it to clear up. :) He had a positive culture so it IS ringworm. Thanks! I enjoy your Web Site, appreciate you taking the time to answer mine and others questions. Meow! ----A thanks from my cat, *Carrots* , Sherry

A: Sherry and Carrots - The current thinking on ringworm seems to be that oral (parenteral) medications are the only ones that are really effective at controlling ringworm. This is a confusing disease to measure treatment efficacy for because it is usually self-limiting and will clear up on its own. Griseofulvin (Fulvicin Rx) does sometimes cause liver damage and it can cause birth defects if used in a pregnant cat or dog. It stops the contagiousness of ringworm pretty quickly, though. It is also the most likely medication to work in resistant cases (those that aren't going to clear up on their own). Due to these benefits we use griseofulvin for the treatment of confirmed cases of ringworm in our practice. So far we have only had to withdraw it in two or three cases. None of our patients died but it would have been better if we hadn't given them a medication that made them sick. This is where analyzing the "risk/benefit" ratio comes in --- most of the time it is better to use griseofulvin. It is just necessary to be careful and to consider the possibility that side effects will occur. Report any changes in temperament, appetite or general health to your vet. Mike Richards, DVM

Last edited 01/03/04


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...