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

Abstract

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

Biology, diagnosis and treatment ofMalasseziadermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

“…Malassezia yeasts were identified by cytological methods in 10–31% of examined anal sacs in two studies of groups of healthy dogs (n = 57), usually in low numbers . Malassezia yeasts were detected on the periocular skin of only three out of 56 (5%) clinically normal dogs . Basset hounds show a marked breed variation, with significantly increased frequencies and population sizes of M. pachydermatis in the nose, mouth, vulva and axilla …”

Repeatability and reproducibility of microscopic examination of adhesive tape strip cytology slides for the quantification ofMalasseziaspp. in canine skin

“…There is no consensus on the optimal microscopic magnification when examining cytological slides for the presence and count of Malassezia yeasts. Although current World Association for Veterinary Dermatology guidelines state that it may be preferable to examine the slides at OI, 1 and this magnification has been used more often in (semi‐)quantitative cytological studies, 7,9–11,13,14,17,19–21,23–29 there are some publications where HP has been employed 12,18,30 . Malassezia cells do not always have the easily recognisable peanut shape that is associated with their monopolar budding, yet they also can appear as round or oval organisms 31 .…”

“…7,[9][10][11]14,[16][17][18] Adhesive tape strip is the most commonly used sampling technique. 1,[5][6][7][8][10][11][12][13][14]17,[19][20][21][22][23][24][25][26][27][28] However, the optimal microscopic magnification, that may be either ×400 (high-power; HP) or ×1000 (oil immersion; OI), 1,5 and the number of optical fields that should be examined have not been standardised, even though they may have a profound impact on the sensitivity, specificity, repeatability and reproducibility of the examination. The aim of this study was to find the optimal microscopic magnification and the minimum number of optical fields that should be examined to achieve the best possible intraobserver repeatability and interobserver reproducibility for the quantification of Malassezia spp.…”

“…Furthermore, trials on the efficacy of various treatments for canine Malassezia dermatitis have been based on the quantitative or semiquantitative microscopic examination of cytological slides 7,9–11,14,16–18 . Adhesive tape strip is the most commonly used sampling technique 1,5–8,10–14,17,19–28 . However, the optimal microscopic magnification, that may be either ×400 (high‐power; HP) or ×1000 (oil immersion; OI), 1,5 and the number of optical fields that should be examined have not been standardised, even though they may have a profound impact on the sensitivity, specificity, repeatability and reproducibility of the examination.…”

Blepharitis in dogs: a clinical evaluation in 102 dogs

“…Blepharitis is defined as inflammation of the eyelid and lid margin; it usually represents a clinical sign of primary ocular and/or cutaneous disease . However, allocation of cause to either an ophthalmological or a dermatological disease can be difficult.…”