Zoonotic - Ringworm


Ringworm Transfer from Cats to Humans?

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 recieved 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 tites. 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 cholorine 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  


Ringworm on Yorkie

Q: When we bought Misty, a four-year-old Yorkie, from our neighbors last August, she had some crusting on her ear rims. We took her to the vet for a genenral checkup, and he diagnosed it as ringworm. He used an ultraviolet light and did some skin scrapings. He told the onsite groomer to try to get as many of the scales off as possible during bathing, to use a special shampoo and let it stay on her for 10 minutes before rinsing, and told her to sanitize everything after so as not to infect other animals there. He told me to go home and launder everything she comes in contact with in hot water and Clorox. He prescribed Tresaderm (15 ml), Fulvicin (125 mg), and Dermazole shampoo. I took her back to him one month later and he said she was progressing nicely, to continue the Tresaderm and Dermazole shampoos, and if her ears looked ok in a few weeks we would not have to come back for this problem. I liked this vet but he was a loooong drive from us. In the interim, a new vet opened shop in the new strip mall around the corner from us. When Misty developed a back problem and was in obvious pain ( to be addressed another time), I took her over there because I did not want her to have to suffer a long car ride at traffic time. For the ear problem, he renewed the prescription for the Tresaderm and also recommended I purchase Hesaseptic Flush Plus and use it twice a week to remove a little wax.

On December 10, vet #2 did a fungal culture that came up negative. He then prescribed Liquichlor ointment to be used on her ear rims and recommended that I remove as much of the crusting as possible. He also said to wash her in Nusal-T shampoo. His diagnosis was ear margin dermatosis (seborrhea). In March vet #2 spayed her and cleaned her teeth, which were slightly infected but not bad enough for her to lose any. Ten days later he took her stitches out and we noticed a little crusting/flaking on her chest. He said it was a staph infection and it looked like it was healing.

On April 10 we saw vet #2 again because the skin crusting was spreading. He said it was still the staph infection and prescribed Cefatabs (100 mg, one pill twice a day), and Hydroxyzine (10 mg, one pill twice a day). He advised us to return if it wasn't better in two weeks. This past Saturday night I felt a dry patch on my cheek while reading in bed. I had my suspicions. The next day, I saw a small circular flaky patch on my lower left cheek, just where her head rests when I carry her down and up the stairs to take her outside. I had been monitoring her all along and was restraining myself from taking her back to the vet before the meds had two weeks in which to work. By Sunday, the flakiness seemed to have spread and also risen in an upward fashion. Took her in Monday and he wasn't convinced it was ringworm until he used the ultraviolet light...boy did she glow green! My dermatologist will see me on Friday to treat my ringworm. The vet prescribed Fulvicin (250 mg, 1/4 pill twice a day) and Dermazole shampoo to be used every five days. He said to let it sit on her 15 minutes and then try to scrub the crusts away. (Unfortunately, she has longish hair and it's hard to know where they all are...and I don't think any groomer would want to htrim her now!) He also said to continue with the Cefatabs until they're gone (another 7 days) and to use the Hydroxyzine as needed to control her itching. We're to report back in three weeks.

I don't know what to do to prevent my husband from getting this and to prevent Misty and me from reinfecting each other and infecting him. Vet #1 said to wash everything in hot water and Clorox. Vet #2 didn't seem to know what we should do. He did say to wash her feed bowls out with a water/Clorox solution, but to do that only once. Should I wash everything Misty (who sleeps with us) and I come into contact with, including sheets, pillow cases, quilts, towels, and all dog linens (bunkies, baby blankets and quilts, crate quilt, and three dog bed covers) in hot water and Clorox? If so, how often? Daily? Every five days when I shampoo her with the Dermazole? Once a week? And what do I do to "de-ringworm" the upholstered recliner we share along with the couch and loveseat she naps on and upon which she rubs her ringwormy face? Would a Lysol/water solution lightly sponged over the upholstered furniture take care of the ringworm spores and prevent us from reinfecting ourselves? If so, which Lysol product, the cleaner or the "straight" stuff, how much cleaner mix with how much water, and how often? I just do not know what to do. Our bed linens and towels will be destroyed with too much hot water and Clorox, and I don't think the upholstered furniture will fare too well if "washed" with Lysol too often...but if I must, then I must.

Also, do you think it is time to take Misty to a veterinary dermatologist? We're in Irving, Texas, and we have access to Texas A&M, but I do not know if a veterinary dermatologist and/or Texas A&M require a referral, which we do not have. Her ear rims did not glow, but, as I understand it, the ultraviolet light does not catch ringworm about 50 percent of the time. Wouldn't it be ironic if that's what she had all along and vet #1 was correct?

One more thing...I usually use tearless puppy shampoo on her head and face and whatever current medicinal shampoo prescribed for her on the rest of her body because I do not want to risk getting anything harsh in her eyes. Vet #2 said not to use the puppy shampoo, to use the Dermazole instead all over her, but to avoid getting it in her eyes (yeah, right) and to put a drop of mineral oil in each eye first. This sounds almost impossible. And I have to let it sit on her for 15 minutes before I rinse it off. Yet she does have this crud on her forehead. She's such a little thing and so sweet, and she gets scared very easily, as we all would if we lived in a world of benevolent giants who nonetheless imposed their will on us. My previous dog, a miniature poodle, seemed to intuitively know that anything uncomfortable I did to her was to help her. This one just gets scared. I've written you a small novel, and I apologize for that. There are a lot of questions buried in this narrative. Thanks for any help you can provide.

A: The most recent information I have seen on ringworm (dermatophytosis), a fungal infection, suggests that only systemic medications like griseofulvin are really effective in treating dermatophytosis. There is evidence that using anti-fungal shampoos is helpful, though. Griseofulvin stops the infectivity of the fungus pretty quickly but may take 6 weeks to clear the infection entirely.

Dilute bleach solutions are effective in killing residual ringworm but I read recently that the single most effective environmental control is vacumning. By thoroughly vacuuming the house and then throwing away the vacuum cleaner bag each time for several weeks it is possible to lessen the number of fungal spores significantly. Clean the things you can with dilute bleach (like waterbowls) and then vacuum everything else well.

It would be a good idea to be sure you do have a ringworm infection, even though that does seem very likely. It isn't sufficient to do a Wood's lamp test in diagnosis of ringworm since there can be both false positive and false negative fluorescence. Fluorescent hairs should be cultured to confirm the ringworm.

It probably isn't necessary to go to Texas A&M at this point but that is a good option if the problem continues despite therapy.

Hope this helps.

Mike Richards, DVM  


Ringworm or Flea Allergy Dermatitis?

Q: I have an 8 year old spayed female tabby. She has been happy & healthy up until a month or so ago. She is strickly an indoor cat. She suddenly starting getting small bald patches down her back. They seem to run along the sides of her spine, identical on each side like a domino. There doesn't seem to be any open sores or rash appearance on these sights but the fur around the bald spots feels slightly hard. She does wash herself on these areas more than normal but I don't know if this is a behavioral or medical problem. She is eating and drinking normally. I have started keeping her in the cellar isolated from our other cat and my baby because I don't know if it could be something contagious. I don't have a lot of money for medical expences but I really want to take good care of my cat. I'm afraid it could be ringworm. Any info on what types of skin conditions it could be would be greatly appreciated.

A: Ringworm (a fungal infection) is the big worry when it comes to cat skin diseases that are contagious to people. Ringworm is tough to rule out when there is patchy hairloss in cats without doing a culture for it. This is not usually too expensive to do. Ringworm can mimic a lot of other skin problems but most of the time when we see it there is some scaling or scabbiness, too.

It would be unusual for the condition to be psychological with the pattern you are seeing but that is also not impossible. Most of the time, pyschological licking/chewing behaviors leading to bald spots seem to show up in the abdominal and inquinal regions (on the cat's underside). If this is psychological, it might make it worse to separate her from the family, causing even more stress.

The most common problem in my area leading to hairloss on the top of the cat is flea allergy dermatitis or other allergic skin disease. This would not be contagious and there would be no risk to the family. Determining if it is going on might allow her to return to being more a part of the family.

I don't know of any sure way to help you decide which skin problem is more likely at home. It would be best to schedule a visit with your vet as soon as it is feasible. Skin disease is usually a lot easier to treat if treatment can be started early in the disease.

Mike Richards, DVM


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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...