Demodicosis of ophthalmic concern. Am J Ophthalmol. 1981;91:362â72. 2. Kemal M, Sumer Z, Toker MI, Erdogan H, Topalkara A, Akbulut M.. The prevalence.
70th AIOC Proceedings, Cochin 2012 This paper was conferred with the AIOS APOS PRADEEP SWARUP AWARD for the BEST PAPER of EXTERNAL DISEASES Session.
Demodex Blepharitis: Indian Scenario Dr. Pawan Prasher Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar Demodex folliculorum is a mite incriminated in the development of blepharitis. To examine their relationship in Indian population, a comparative study was carried out on eyelashes of 72 patients with diagnosis of blepharitis and 72 healthy individuals. Following routine ophthalmological evaluation, microscopic examination of epilated eyelashes was performed as per previously described protocol in literature. Demodex mite was seen in 31 of 72 (43.05%) patients with blepharitis and 8 of 72 (11.11%) in control group. The incidence was higher in males, elderly and in individuals with increased severity of blepharitis. Higher incidence of Demodex folliculorum in blepharitis patients suggests that it plays a key role in producing clinical manifestations of blepharitis
D
emodex folliculorum, a hair follicular mite, is the most common microscopic ectoparasite that lives in the hair follicles and sebaceous glands especially of the face. Among the various species, only two have been described on the human body surface: Demodex folliculorum longus and Demodex folliculorum brevis. Demodex folliculorum longus is commonly found in the infundibular portion of pilous follicle of the eyelash. Demodex folliculorum brevis is found in the deep ducts of sebaceous glands of the eyelash and meibomian glands. Once Demodex infestation establishes in the face, it is likely to spread and flourish in the eyelids leading to blepharitis. Despite this, the clinical significance of Demodex infestation remains debatable in part because it can also be found in asymptomatic subjects. The purpose of this study was to understand the relationship between Demodex infestation and blepharitis by comparison of its prevalence in patients with blepharitis to normal controls in Indian population.
MATERIALS AND METHODS The current study included 72 patients with the diagnosis of blepharitis and 72 healthy age and sex matched controls. Following routine ophthalmological evaluation, microscopic examination of epilated eyelashes was performed. Under slit lamp microscope magnification, two lashes, one from each half of each lid, were removed by fine forceps and placed separately on glass slides. To prevent the free Demodex from floating away from the lash, a coverslip was mounted and slow application of saline was done at the edge of the coverslip to surround the lash. Under the microscope, blepharitis scales and follicles were examined for the presence of Demodex.
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RESULTS Demodex mite was seen in 31 of 72 (43.05%) patients with blepharitis and 8 of 72 (11.11%) in the control group. Further analysis of the study group showed that the prevalence was higher in males, elderly and in individuals with increased severity of blepharitis (Table 1). Table 1: Prevalence of Demodex infestation based on demographic and clinical characteristics in the study group Age
Number of patients
Demodex positive
Percentage
70
11
9 81.8
Grading of blepharitis Mild
14
3 21.4
Moderate
36
11 30.5
Severe
22
17 77.2
Male
38
19
Female
34
12 35.2
Sex 50
DISCUSSION The higher prevalence of Demodex in the study group as compared to controls in the current study suggests that it plays a key role in pathogenesis of blepharitis. The pathogenesis of Demodex blepharitis includes direct mechanical damage by the mites resulting in follicular distension that may contribute to loose or misdirected cilia. Microabrasions caused by the claws of the mite can lead to reactive epithelial hyperplasia and hyperkeratinization which is clinically manifested as cylindrical dandruff at the base of eyelashes. Demodex mite may also act as vector for bacteria and its wastes or debris may ellicit inflammatory response via delayed hypersensitivity or innate host response. The higher prevalence of Demodex in males can be attributed to higher number of sebaceous glands in the males. Also, the use of eye make-up in females may play a role as chemicals in the make-up may be toxic for the mites. Further, individuals who frequently apply make-up are likely to clean their facial skin more regularly and thus have better lid hygiene. The prevalence of Demodex infestation increases with age. The newborns are free from mites and individuals get colonized while growing up from adult family members. The higher rate in elderly can also be attributed to declining
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level of hygiene secondary to reduced activity with ageing. The higher prevalence of Demodex in more severe cases can be attributed to higher degree of colonization of hair follicles by the mites that in turn may be responsible for increased severity of blepharitis which is refractory to conventional treatment. Higher prevalence of Demodex folliculorum in blepharitis patients suggests that it plays a key role in producing clinical manifestations of blepharitis. Further studies are needed to determine whether continued presence of this mite in the eyelids is responsible for lack of response to conventional treatment in patients suffering from blepharitis, a scenario not uncommon in routine ophthalmology practice.
REFERENCES 1. English FP, Nutting WB. Demodicosis of ophthalmic concern. Am J Ophthalmol 1981;91:362–72. 2.
Kemal M, Sumer Z, Toker MI, Erdogan H, Topalkara A, Akbulut M.. The prevalence of Demodex folliculorum in blepharitis patients and the normal population. Ophthalmic Epidemiol. 2005;12:287-90.
3. Uyttebroeck W, Nijs I, Maudgal PC, Missotten L. Incidence of Demodex folliculorum on the eyelash follicle in normal people and in blepharitis patients. Bull Soc Belge Ophtalmol 1982;201:83–7. 4.
Türk M, Oztürk I, Sener AG, Küçükbay S, Afar I, Maden A. Comparison of incidence of Demodex folliculorum on the eyelash follicule in normal people and blepharitis patients. Turkiye Parazitol Derg. 2007;31:296-7.
Best of Best Free Papers 5. Liu J, Sheha H, Tseng SC. Pathogenic role of Demodex mites in blepharitis. Curr Opin Allergy Clin Immunol. 2010;10:505-10. 6. Inceboz T, Yaman A, Over L, Ozturk AT, Akisu C. Diagnosis and treatment of demodectic blepharitis. Turkiye Parazitol Derg. 2009;33:32-6.
