Demodicosis Clinical Presentation
- Author: Manolette R Roque, MD, MBA, FPAO; Chief Editor: Hampton Roy, Sr, MD more...
Symptoms include ocular irritation, itching, and scaling of lids. Past ocular history may include recurrent failed treatment of blepharitis.
Gross observation may reveal the following:
Scaling of lids
Madarosis (loss of lashes)
Meibomian gland dysfunction
Rosacea: The results of the study by Moravvej et al  conclude that the prevalence and the number of Demodex mites in rosacea patients are higher than in control subjects, supporting the pathogenic role of Demodex mites in rosacea.
Slit-lamp findings are as follows:
Collar of tissue around the base of the eyelashes
Cornea - Superficial corneal vascularization, marginal corneal infiltration, phlyctenule-like lesion, superficial corneal opacity, nodular corneal scar
Demodex species specific to humans occupy 2 periocular sites hidden from external observation. They are small in size and possess the ability to move across the skin surface.
D folliculorum is found in hair and eyelash follicles associated with pilosebaceous glands in the eye or elsewhere on the face and the body. A single follicle may contain as many as 25 D folliculorum organisms.
D brevis leads a much more solitary lifestyle in sebaceous glands of the body and in the meibomian gland and the gland of Zeis.
D folliculorum measures 0.3-0.4 mm in length, whereas D brevis is one half the size of D folliculorum (0.15-0.2 mm) with similar structure of the head and the thorax but a shorter abdomen.
The 8 legs of this arachnid are segmented and provide locomotion at a rate of 8-16 mm/h.
D folliculorum and D brevis, also known as follicle mites, are believed to be more active in the dark, although capture in daylight is possible.
The bright light of the day and especially the biomicroscope cause the mite to recede back into the follicle. Therefore, the mite can be observed only when an epilated lash is observed under a low-power microscope.
The life stages of D folliculorum begin with copulation at the mouth of the follicle. Reproduction is believed to occur in darkness; a fact that is significant in symptomatology and treatment.
Following copulation, the female burrows back into the follicle near the opening of the pilosebaceous gland and lays her eggs.
Spickett reported the life cycle of D folliculorum and estimated that only 14.5 days elapse from ovum to adult stage, including 120 hours as an adult. Females may live an additional 5 days after oviposition.
Sexes are separate; sexual maturity is reached in the larval form (neoteny).
Females are territorial; they remain in their respective follicles and wait for the nomadic philandering males that travel over the surface of the skin from one follicle to another in seek of females.
Adults reside in the follicle parallel to the hair shaft, head inward, often with the tail end (opisthosoma) protruding onto the surface of the skin at the base of the eyelash.
Coston TO. Demodex folliculorum blepharitis. Trans Am Ophthalmol Soc. 1967. 65:361-92. [Medline].
Ayres S Jr. Demodex folliculorum as a pathogen. Cutis. 1986 Jun. 37(6):441. [Medline].
Spickett SG. Studies on Demodex folliculorum, Simon (1842). I. Life history. Parasitology. May 1961. 51:181-192.
Post DF, Juhlin E. Demodex folliculorum and blepharitis. Arch Dermatol. 1963. 88:298-302.
Liang L, Safran S, Gao Y, Sheha H, Raju VK, Tseng SC. Ocular demodicosis as a potential cause of pediatric blepharoconjunctivitis. Cornea. 2010 Dec. 29(12):1386-91. [Medline].
Moravvej H, Dehghan-Mangabadi M, Abbasian MR, Meshkat-Razavi G. Association of rosacea with demodicosis. Arch Iran Med. 2007 Apr. 10(2):199-203. [Medline].
Kheirkhah A, Blanco G, Casas V, Tseng SC. Fluorescein dye improves microscopic evaluation and counting of demodex in blepharitis with cylindrical dandruff. Cornea. 2007 Jul. 26(6):697-700. [Medline].
Celerio J, Fariza-Guttman E, Morales V. Pilocarpine as a coadjuvant treatment of blepharoconjunctivitis caused by Demodex folliculorum. Invest Ophthalmol Vis Sci. 1989. 30 (Suppl):40.
Gao YY, Di Pascuale MA, Elizondo A, Tseng SC. Clinical treatment of ocular demodicosis by lid scrub with tea tree oil. Cornea. 2007 Feb. 26(2):136-43. [Medline].
Gao YY, Di Pascuale MA, Li W, Baradaran-Rafii A, Elizondo A, Kuo CL, et al. In vitro and in vivo killing of ocular Demodex by tea tree oil. Br J Ophthalmol. 2005 Nov. 89(11):1468-73. [Medline]. [Full Text].
Gao YY, Xu DL, Huang lJ, Wang R, Tseng SC. Treatment of ocular itching associated with ocular demodicosis by 5% tea tree oil ointment. Cornea. 2012 Jan. 31(1):14-7. [Medline].
Cliradex instructional video. Available at http://www.youtube.com/v/OljcnbghoR8?hl=en&fs=1.
Beaver PC, Jung RC, Cupp EW. Clinical parasitology. Clinical Parasitology. 9th ed. Philadelphia, Lea & Febiger: 1984. 596.
Forton F, Germaux MA, Brasseur T, De Liever A, Laporte M, Mathys C, et al. Demodicosis and rosacea: epidemiology and significance in daily dermatologic practice. J Am Acad Dermatol. 2005 Jan. 52(1):74-87. [Medline].
Gao YY, Di Pascuale MA, Li W, Baradaran-Rafii A, Elizondo A, Kuo CL, et al. In vitro and in vivo killing of ocular Demodex by tea tree oil. Br J Ophthalmol. 2005 Nov. 89(11):1468-73. [Medline].
Kheirkhah A, Casas V, Li W, Raju VK, Tseng SC. Corneal manifestations of ocular demodex infestation. Am J Ophthalmol. 2007 May. 143(5):743-749. [Medline].
Cheng AM, Sheha H, Tseng SC. Recent advances on ocular Demodex infestation. Curr Opin Ophthalmol. 2015 Jul. 26 (4):295-300. [Medline].
Hirsch-Hoffmann S, Kaufmann C, Bänninger PB, Thiel MA. Treatment options for demodex blepharitis: patient choice and efficacy. Klin Monbl Augenheilkd. 2015 Apr. 232 (4):384-7. [Medline].
Filho PA, Hazarbassanov RM, Grisolia AB, Pazos HB, Kaiserman I, Gomes JÁ. The efficacy of oral ivermectin for the treatment of chronic blepharitis in patients tested positive for Demodex spp. Br J Ophthalmol. 2011 Jun. 95 (6):893-5. [Medline].