(A follicle is the pore from which a hair grows). Demodicids have a wormlike appearance, with legs that are mere stumps. People with oily skin, or those who use cosmetics heavily and don't wash thoroughly, have the heaviest infestations ... but most adults carry a few demodicids. Inflammation and infection often result when large numbers of these mites congregate in a single follicle.
The mites live head-down in a follicle, feeding on secretions and dead skin debris. At the left, you can see three demodicids buried in the follicle of a hair, and you can also see the hair's shaft. If too many mites have buried into the same follicle, it may cause the eyelash to fall out easily.
An individual female may lay up to 25 eggs in a single follicle, and as the mites grow, they become tightly packed. When mature, the mites leave the follicle, mate, and find a new follicle in which to lay their eggs. The whole cycle takes between 14 to 18 days.
Sometimes demodex is called the 'face mite', since it is often associated with blackheads, acne and other skin disorders (although it is not the cause of these). Demodex are harmless and don't transmit diseases, but large numbers of demodex mites may cause itching and skin disorders, referred to as Demodicosis.
The mites have tiny claws, and needlelike mouthparts for eating skin cells. Their bodies are layered with scales, which help them anchor themselves in the follicle. The mite's digestive system results in so little waste that the mite doesn't even have an excretory opening. So although there may be mites in your eyelashes, there isn't any mite poop! Thank goodness!
However ... did you know that you go to sleep at night on a pillow that is home to many thousands of dust mites ...which help keep our homes clean by consuming the tens of millions of skin cells we shed each day? Just pretend they're not there!
So guys, please don't try to go look in the mirror. You need a microscope and one of your eyelashes to see these little guys. Happy grooming, fright fiends! ;-)