Llama Dermatology

Abstract

As llamas become more common in North America, veterinarians will be called on ever more frequently to deal with their dermatologic problems. Adherence to the basic tenets of the thorough dermatologic work up, including history, physical examination, skin scrapings, cytological examinations, fungal culture, skin biopsies, and assessing response to judiciously chosen trial therapies will offer the best opportunity of arriving at proper diagnoses. Special attention must be paid to the fact that llama skin bears some histological differences that may prove confusing to the uninitiated. A mild degree of hyperkeratosis, a prominent vascular plexus in the superficial dermis that is associated with mild perivascular mononuclear cell accumulations, and regional differences in sebaceous gland size and numbers, all are considered normal findings. Ectoparasites, including sarcoptic mange, chorioptic manage, and pediculosis, appear to be the most common causes of pruritus in the llama. Although ivermectin therapy would appear to be very effective for the treatment of scabies and, indeed, may work well against sucking lice, chorioptic mange and biting lice usually do not respond to this medication. Corticosteroids can be used to treat pruritus in the llama nonspecifically, using the anti-inflammatory dosages established in other species. These drugs are used most appropriately for the management of the allergies that we suspect occur in this species, until better alternative therapies can be developed. Variably pruritic focal areas of alopecia, exudation, and crusting suggest differential diagnoses including bacterial folliculitis and furunculosis, dermatophilosis, dermatophytosis, and coccidioimycosis. The diagnosis of bacterial problems often is made by assessing response to antibiotic therapy. Topical disinfectants and/or systemic penicillin or trimethoprim-sulfadiazine are indicated. Dermatophilosis is treated by cleaning and drying the leasions, applying topical antibiotics, and, occasionally, using parenteral penicillin and streptomycin. Dermatophytosis usually is treated with topical antibiotics only. Captan is one of several therapies of choice. There is no therapy presently available for coccidioidomycosis in the llama. Perhaps most perplexing is the fact that one of the most common dermatopathies seen in the llama is an idiopathic keratinizing disorder that, in some cases, is responsive to zinc supplementation. We have no real idea of the pathogenesis of this problem and recognize that some affected animals will not respond to supplementation.(ABSTRACT TRUNCATED AT 400 WORDS)