Griseofulvin is the preferred treatment for dermatophytes but has occasionally been used for its anti-inflammatory effects
in skin diseases in cats. Its dosage for the feline eosinophilic granuloma complex is similar to its use in treating dermatophytes
at 25 mg/kg twice daily with food. This dosage should be given for at least one month to judge efficacy. Chlorambucil (Leukeran)
is an alkylating agent that alters DNA synthesis. Its mechanism of action in the treatment of the eosinophilic granuloma complex
is not understood. It is given at a dosage of 0.1-0.2 mg/kg daily and often in conjunction corticosteroids. Daily treatment
is continued for four weeks and then changed to alternate days; the lowest possible dosage should be used. Toxicity is uncommon
but reversible bone-marrow suppression does occur, and cats on chlorambucil should be monitored with CBCs and platelet counts
every two to four weeks. Vomiting, diarrhea and anorexia have also been seen, but tend to resolve when the medication is given
on alternate days.
Canine eosinophilic granuloma is most commonly reported in Arctic dog breeds and most often is seen on the inner thighs or
in the mouth. Erythematous to yellow raised nodules with papillated surfaces are typical. Pruritus is variable. Diagnosis
is by histopathologic examination that shows eosinophils and granulomatous inflammation around eosinophilic debris-coated
collagen. Treatment is with prednisone at 1 mg/kg q12h for one week, then tapering down during the course of four to six weeks.
Occasionally, higher initial dosages are necessary.
Canine eosinophilic furunculosis probably is a related disease. It occurs in many dog breeds but typically is seen in
long-nosed large breeds or curious small breeds (i.e., terriers) with potential access to wasps, bees, ants, spiders and other
venomous insects. The disease can be very rapid in onset, leading to nasal/muzzle swelling, exudation and pain. Large, swollen,
erythematous lesions on the muzzle are the most common lesions, but similar lesions may be seen on the head, around the eye
and pinna in some dogs. Impression smears often will show eosinophils. While diagnosis usually is done on a clinical basis,
histopathologic confirmation will show lesions similar to that of the canine eosinophilic granuloma, but with more eosinophilic
infiltration into the epidermis and follicular wall, a furunculosis, and fewer areas of eosinophilic debris-coated collagen.
Treatment is the same for the canine eosinophilic granuloma.
By Johnny D. Hoskins
DVM, Ph.D., Dipl. ACVIM
Dr. Hoskins is owner of DocuTech Services. He is a diplomate of the American College of Veterinary Internal Medicine with
specialities in small animal pediatrics. He can be reached at (225) 955-3252, fax: (214) 242-2200, or e-mail: