Malassezia spp on the periocular skin of dogs and their association with blepharitis, ocular discharge, and the application of ophthalmic medications

• Autores: Georgina M. Newbold
• Localización: JAVMA: Journal of the American Veterinary Medical Association, ISSN-e 0003-1488, Vol. 244, Nº. 11, 2014, págs. 1304-1308
• Idioma: inglés
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• Resumen

  • Objective—To determine how frequently Malassezia spp were identified on the periocular skin of dogs and assess the respective associations between the presence of Malassezia spp on the periocular skin and blepharitis, ocular discharge, and the application of ophthalmic medications.

    Design—Prospective clinical study.

    Animals—167 eyelids of 84 dogs.

    Procedures—Samples obtained from the surface of the eyelid skin by use of adhesive tape were evaluated cytologically for the presence of Malassezia spp. Dogs were grouped on the basis of the presence of blepharitis, nature of ocular discharge, and whether ophthalmic medications were applied, and the proportion of samples with Malassezia spp was compared among the groups.

    Results—Malassezia spp were detected in 19 samples, of which 15 were obtained from eyes without blepharitis and 14 were obtained from eyes treated with topical ophthalmic medications. The proportion of samples with Malassezia spp was significantly higher for eyes with ocular discharge than for eyes without ocular discharge, especially if that discharge was mucoid or mucopurulent, and for eyes that were treated with aqueous-based medications only or a combination of oil- and aqueous-based medications than for eyes that were not treated.

    Conclusions and Clinical Relevance—Malassezia organisms were detected on the periocular skin of 3 of 56 (5%) clinically normal dogs. Malassezia organisms were also frequently found on the periocular skin of dogs that had mucoid or mucopurulent ocular discharge or that were administered topical aqueous-based ophthalmic medications, and the periocular skin of these dogs should be cytologically evaluated for Malassezia organisms. (J Am Vet Med Assoc 2014;244:1304–1308) Malassezia spp are lipophilic and often lipid-dependent yeasts that are common commensal organisms on the skin and ears of dogs but can also cause dermatologic and aural disease.1 In veterinary medicine, one of the most clinically important species is Malassezia pachydermatis, which is an opportunistic pathogen commonly associated with canine dermatitis and otitis externa secondary to other diseases that result in abnormal sebaceous or ceruminous secretions. In dogs, the distribution of Malassezia spp is dependent on the location of skin sampled, disease status of the animal, and the method used for detection. Malassezia spp have been detected by cytologic evaluation in 40 of 99 (40%) healthy ears and 83 of 101 (82%) diseased ears,2 and by culture of the organism from samples collected by the use of sterile cotton swabs moistened with sterile saline (0.9% NaCl) solution to swab the skin of healthy dogs in various locations on their bodies.3 In the study3 that used culture as a means to identify Malassezia spp, the perianal area was the area most frequently colonized (20/33 [61%]), the inguinal area was the area least frequently colonized (1/33 [3%]), and Malassezia spp were cultured from the periorbital region of 3 of the 33 (9%) healthy study dogs. To our knowledge, studies have not been conducted in which the frequency of Malassezia colonization of the periocular region of healthy dogs was determined by cytologic examination. Furthermore, studies to investigate the association of Malassezia spp with blepharitis or periocular dermatitis are lacking but are warranted given that topical application of oil-based ophthalmic medications may affect the lipid composition of the periocular dermal microenvironment, which could promote the growth of Malassezia spp on the eyelid skin.4 Additionally, many commonly used topical ophthalmic medications contain immunosuppressive agents such as corticosteroids, cyclosporine, or tacrolimus that might alter the cutaneous immunity and microflora of the periocular region. Malassezia spp can induce inflammation by either nonspecific mechanisms or antigen-specific hyper-sensitivity reactions.5 Thus, proliferation of Malassezia organisms in the periocular region could cause changes in the skin and localized dermatitis or blepharitis, particularly in patients that are hypersensitive to Malassezia. The purpose of the study reported here was to determine how frequently Malassezia spp were identified on the periocular skin of dogs with or without blepharitis and to evaluate the respective associations between the presence of Malassezia spp on the periocular skin and the presence of blepharitis, the presence and type of ocular discharge, and the topical application of oil-based, aqueous-based, or potentially immunosuppressive ophthalmic medications.