Ringworm, microsporum, dermatophyte, fungus, fungal, itchy, round, raised, hair loss, outdoors, immune, infection, contagious, anti fungal
The first point I want to make about ringworm is that, despite what is implied by its name, it is not a worm! Ringworm, or microsporum, is actually a dermatophyte, or a fungal infection which invades active hair follicles. The infection caused by this fungal organism presents as a raised, crusty, round, sore, thus the name "ring" worm, which is very itchy. The fungal spores can spread easily to other pets, or even to people, in the household, or to other areas on the pet's body. The typical presentation is that of a round, raised, itchy sore which has already lost most of the hair inside the circle, or one from which the hair epilates easily. The lesion is found in cats and dogs, though many people seem susceptible to the infection as well.
The fungus is usually transmitted from pet to pet or pet to people. The fungal spores do, however, survive in soil, so it is possible for pets, especially outdoor cats who roam freely, to contact the disease from the environment. If one pet in the household is diagnosed with a ringworm infection, it would be very wise to minimize contact with that pet. As with many parasitic infections there does seem to be some link to an animal's immune system and its susceptibility to a ringworm infection. We definitely see a higher incidence of the disease in immune-compromised animals. Likewise we often see cases with many pets in a household, yet only one acquiring the infection.
Besides the obvious appearance of the typical ringworm lesion, an accurate diagnosis is made either by finding fluorescence using an ultraviolet light known as a wood's lamp, though only about 50 percent of microsporum infections will fluoresce under the wood's lamp, by identifying the characteristic hyphae and spores culturing a sample of the lesion using a dtm test medium, or by microscopic identification.
Once an accurate identification is made, treatment should be started as soon as possible. Sounds easy-but it isn't always so. Firstly, many ringworm infections are difficult to treat. Also, there are a number of treatment options available, ranging from special dips, topical creams and solutions, to any number of oral anti-fungal medications. The choice is dependent upon your doctor's preferences, cost, and the severity of the infection. Because the health status of these pets is often compromised, it will be necessary to run a blood and urine analysis to evaluate your pet's overall health prior to treatment. Often, depending on how generalized the infection is, it may be recommended to have your pet shaved-which may not be a bad idea. Most of us prefer the topical treatment options---special baths followed by topical creams or solutions, but occasionally, with very generalized or refractory infections, the oral anti-fungal medications may be necessary.
The good news is that with good care and a little tenacity, the vast majority of pets will recover from their ringworm infections. For more information, check with your veterinarian.