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Are the mites having a party on your eyelids?

Do you wake up with early morning itching and irritation around your eyelids?  Have a lot of crusting build up around the eyelashes?

Your eyelids may be the unwitting host to be a nightly demodex mite party!

Demodex mites are the most common microscopic ectoparasite found in the human skin. The rate of Demodex infestation increases with age, being observed in 84% of the population at age 60 and in 100% of those older than 70 years (Post & Juhlin, 1963).

There are primarily two mites principally involved in human demodex infestation (demodiscosis); Demodex Brevis (D. brevis) and Demodex Folliculorum (D folliculorum).  D. brevis  is smaller 0.15-0.2mm and is found in the oil glands that are connected to small hair follicles.  D. folliculorum are found in small hair follicles, particularly the eyelashes and are 0.3-0.4mm in length.

These little "night ragers" are invisible to the naked eye, but their structure is clearly visible under a microscope. It has a semi-transparent, elongated body that consists of two fused segments.  Eight short, segmented legs are attached to the first body segment allow them to move 8-16 mm/h, mainly done during the night as bright light causes the mite to recede back into the follicle (Rather & Hassan, 2014). The body is covered with scales for anchoring itself in the hair follicle and the mite has pin-like mouth parts for eating skin cells, hormones, and oils (sebum) accumulating in the hair follicles.

The life of a mite is reasonably short, so the mite like to continue their family lines and copulate.  Both male and female Demodex mites have a genital opening and fertilization is internal. Mating takes place in the follicle opening and eggs are laid inside the hair follicles or sebaceous glands. The six-legged larvae hatch after 3-4 days, and the larvae develop into adults in about 7 days. It has a 14-day life cycle. The total lifespan of a Demodex mite is several weeks. The dead mites decompose inside the hair follicles or sebaceous glands .  So your lash area is a party ground, buffet restaurant and burial ground for your invisible friend!

demodex mite

Removed demodex mite with forceps under 40x magnification on examination slit lamp.

Refererences:

POST CF., JUHLIN E. Demodex Folliculorum and Blepharitis.  Arch Dermatol. 1963 Sep; 88():298-302.
Rather PA., Hassan I. Human Demodex Mite:The versatile Mite of Dermatological Importance  Indian J Dermatol. 2014 Jan-Feb; 59(1): 60–66.
demodex folliculorum

Demodex Folliculorum under Scanning Electron Microscope

demodex folliculorum

Demodex Follicolorum under conventional microscope 

demodex blepharitis eyelash collarettes

Eyelashes with collarettes from Demodex Blepharitis

demodex blepharitis eyelashes

The same Eyelashes above after Blephex Clean

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