Pruritus in rabbits, rodents, and ferrets

This article attempts to cover the more specific pruritic problems encountered in rabbits, rodents, and ferrets. There are certainly other causes of pruritus in these animals. Dermatophytes in guinea pigs are not reported to be pruritic, but because they are pruritic in other species, they should be considered in a differential diagnosis. A cryptococcal dermatitis in a guinea pig that was pruritic has been reported. Although mites were not seen on scraping, the animal was treated for sarcoptid mites and apparently the pruritus lessened. Because the cryptococcis was still present, it is questionable whether it was causing the pruritus. Pruritic ulcerative dermatitis over the back and shoulders has been seen in some lines of rats. Staphylococcus aureus was cultured from many of the lesions. Clipping the toenails on the feet helped lessen the severity of the lesions. Syphacia spp. have been reported in rats, gerbils, and hamsters and should be considered if there is perineal pruritus. MOBS, or "move over buddy syndrome," is seen especially in mice and may be seen in hamsters, gerbils, and rats that are overcrowded or stressed. The lesions are actually bite wounds that have been inflicted around the tail base and the perineum and on the tail, but these wounds can be mistaken for self-inflicted trauma from pruritus. All of the recommended treatments are extralabel, and clients should be informed of this. I have observed a guinea pig become lethargic and anorexic after only one application of a flea powder approved for use in cats. Brushing most of the powder off and offering dandelion greens to stimulate appetite helped. The second dusting was done with the same flea powder diluted with baby powder. Whenever these animals are dipped, it is important to let them dry in a warm, draft-free area. Again, it is important to be aware that the ratio of surface area to body weight is much higher in these small animals than in the species routinely seen in veterinary practice especially to prevent toxicoses from topically applied medications and iatrogenic hypothermia or hyperthermia.     

Pruritus: an overview of current concepts

Pruritus is an integral part of the patient's symptoms in numerous dermatological and systemic diseases in humans and animals. Comparable to chronic pain, pruritus can have a dramatic impact on the quality of life of the patient. In recent years, pruritus has been defined as an autonomous, pain-independent sensation, and itch-specific neurons, mediators, spinal neurons and cortical areas have been identified. These observations have not only improved our understanding of the neurobiology of itch but will also lead to improved diagnosis and to the development of new and more efficient therapeutic options. This article reviews the role of itch fibres and their response to various mediators of pruritus including histamine, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), and substance P (SP), and opioids. Substances that may be involved in the induction or modulation of itch may be termed pruritogenic mediators and examples discussed include proteases, lipid mediators, neuropeptides, opioids and various cytokines. There is no single, generally accepted clinical classification of chronic pruritus. In the past pruritus has been classified on the basis of the neuroanatomical origin and on the potential underlying disease. Therapeutic options for the management of pruritus are discussed including topical and systemic therapies, assuming that trigger factors have been eliminated where possible. Topical agents may include capsaicin, the calcineurin inhibitors tacrolimus and pimecrolimus, and cannabinoid agonists such as N-palmitoyl ethanolamine. Systemic therapies may include antihistamines, anticonvulsants, opiate receptor antagonist or agonists, antidepressants, ciclosporin, and UV light.     

Pruritus possibly associated with a portosystemic shunt in a bichon frise puppy

A bichon frise puppy was presented with generalized pruritus. At 22 weeks, a portosystemic shunt was diagnosed. Correction of the shunt led to resolution of the pruritus. Pruritus associated with hepatobiliary disease is well documented in humans; this case suggests that hepatobiliary disease may be associated with pruritus in dogs.