Fungal Infections and Their Treatment
Fungal infections often start on the face as areas of patchy, itchy hair loss. There may be multiple sites, on the back and limbs, especially in warm weather. Harkness and Wagner describe the lesions as "oviod, hairless, scaling "sore spots" with crusts or scabs over raised areas." In guinea pigs, the tufts of hair may be stuck together by a crust of exudate (the skin beneath may exude serum). When this dries up the lesions become dry and scaly. These tufts will fall out and hair regrow in about 4 weeks.
Dermatophytes ("ringworm") include trichophyton mentagrophytes and its variants. While an active infection is not common, many animals can be carriers. Stress, diet, environment, heat and humidity, concurrent infection by external parasites, age (the old, young and pregnant). genetics, and crowding all may predispose animals to an infection.
Top photograph by Lindsaymarie.
2nd photograph by Thibault.
3rd photo by Jandras (miconazole cream cleared this up)
4th photo by Rshevin (miconazole cream also cleared this up - not identified by culture as fungus)
Bottom photograph by Phlumpetta.
Prevention includes prompt treatment of external parasites, good husbandry, and lowering humidity levels. Humid climates may be especially problematic for guinea pigs. The incubation period is reportedly 7 to 14 days for ringworm. This fungus releases a great number of spores into the environment which can be inactive for years so disinfecting the area is important.
A culture can be used for positive diagnosis. Harkness and Wagner recommend cultivating aerobically for at least 10 days at room temperature onto an agar culture medium suitable for growth. Scrapings from the edge of the infected area and examined by microscope may also aid in diagnosis. Some forms of Microsporum canis will fluoresce under an ultraviolet light. Get a positive diagnosis before treating for ringworm.
Treatment: Both the lesions and the ringworm itself must be treated and living area disinfected. Your veterinarian may prescribe a soothing shampoo to loosen debris and help make your animal more comfortable.
Remember that ringworm is contagious.
Isolate infected animals immediately.
Wear protective clothing when handling infected animals (wash hands as necessary or wear rubber gloves).
Soak all equipment and wash cages in a fungicide like LD disinfectant or a dilute solution of bleach (let sit for 15 minutes then rinse).
Remove bedding, discard wood in cages (the spores can be very difficult to remove from wood).
A wide variety of anti-fungal remedies are effective when used to treat fungus. Here are a few of them:
Nizoral is a human antifungal, dandruff shampoo that is currently not easy to find.
Active ingredient Ketoconazole 2%
KetoChlor is a prescription veterinary topical shampoo.
Active ingredients ketoconazole 1% and chlorhexidine gluconate 2.3%
Active ingredients: Chlorhexidine Gluconate 2%, Miconazole Nitrate 2%
Active ingredients 2.0% Chloroxylenol, USP, 1.0% Ketoconazole, USP
Miconazole cream (Monistat 7, Femizol-M – human OTC med), active ingredient: miconazole nitrate 2%
Clotrimazole (Gyne-Lotrimin, Mycelex, Lotrimin, Lotrisone), active ingredient clotrimazole 1%
Lufenuron (Program) Recommended doses vary from 30mg/kg to 45mg/kg to 90 mg/kg. Program seems to have a high range of safety. Pregnant and lactating females can be treated with Program (read thread -- "The lufenuron is found in the milk, but no adverse effects were seen at 10 times the recommended dose."). Must be taken with a fatty meal – perhaps 1cc of flax seed oil for better absorption.
Ketoconazole has also been used orally at 10 to 40 mg/kg/day OS for a couple weeks. (Harkness and Wagner)
Itraconazole (US: Sporonox -- UK: Itrafungol). Lydster writes this is a new drug, rather expensive but apparently effective on ringworm, yeast, and several other fungi. See also: Marvistvet or the UK NOAH site for more information.
Small areas of hair loss can be cleaned with a dilute solution of chlorhexidine gluconate 2% solution (see supplies), dry, then apply miconazole cream to the area twice a day. If the infection is also on the trunk, bathe the animal once a week with one of the listed shampoos for 3 or 4 weeks (avoid the eyes and ears). Dry thoroughly before returning your pet to its cage. Lufenuron can be used to treat difficult cases. Continue treatment until culture shows fungus is gone.