Demodex
Demodex is a genus of microscopic mites that live in or near the hair follicles and sebaceous glands of mammals.
Demodex is a genus of microscopic mites that live in or near the hair follicles and sebaceous glands of mammals. In humans, the best-known species are Demodex folliculorum and Demodex brevis, which are usually harmless but can contribute to demodicosis and some eye or skin conditions when present in high numbers. Demodex is relevant to Canadian dermatology and eye care because it is a common cause or contributing factor in facial skin and eyelid conditions such as demodicosis and blepharitis.
Taxonomy and biology
Demodex is a genus of microscopic mites in the arachnid group. Around 65 species are known, with species adapted to different mammal hosts.
Human-associated species
The two human-associated species are Demodex folliculorum and Demodex brevis. They inhabit pilosebaceous units, with D. folliculorum more associated with hair follicles and D. brevis with sebaceous glands.
Clinical significance
Most Demodex infestations are asymptomatic, but high mite density can lead to demodicosis. The mites have also been linked to blepharitis, ocular rosacea, meibomian gland dysfunction, and some skin diseases.
Transmission and prevalence
Demodex mites are common in adults and tend to increase with age. Human species are generally considered host-specific, and animal Demodex species are not typically transmitted to humans.
Key facts
- Demodex mites are tiny arachnids related to spiders and ticks.
- They live in or near hair follicles and oil glands, especially on the face and eyelids.
- Two species are typically found on humans: D. folliculorum and D. brevis.
- Most people carry Demodex mites without symptoms.
- Overgrowth can cause demodicosis, with itching, irritation, inflammation, or ocular symptoms.
Demodex is relevant to Canadian dermatology and eye care because it is a common cause or contributing factor in facial skin and eyelid conditions such as demodicosis and blepharitis.
Frequently asked questions
What is Demodex?
Are Demodex mites common in humans?
Which Demodex species live on humans?
What problems can Demodex cause?
Do Demodex mites live on the face?
Are animal Demodex mites the same as human ones?
References
- Cleveland Clinic — https://my.clevelandclinic.org/health/diseases/22775-demodex-face-mitesSupports: Human Demodex mites, usual harmlessness, and demodicosis when overgrown.
- ScienceDirect — https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/demodex-folliculorumSupports: Two human species and typical locations on the face and pilosebaceous units.
- ScienceDirect — https://www.sciencedirect.com/topics/immunology-and-microbiology/demodexSupports: Animal Demodex species such as D. canis causing mange in dogs.
- WebMD — https://www.webmd.com/skin-problems-and-treatments/what-are-demodex-mitesSupports: Symptoms, risk factors, common human species, and treatment overview.
- UCLA Health — https://www.uclahealth.org/news/article/up-90-adults-play-host-mitesSupports: Approximately 65 species and two species on humans.
- EyeWiki — https://eyewiki.org/Demodex_InfestationSupports: Commensal relationship, ocular disease associations, and overlooked infestation.
- DermNet NZ — https://dermnetnz.org/topics/demodexSupports: Human locations, two principal species, and demodicosis.
- PubMed Central — https://pmc.ncbi.nlm.nih.gov/articles/PMC3884930/Supports: Obligate ectoparasite, prevalence, asymptomatic infestation, and human species.