Mites are tiny eight-legged creatures, related to spiders and ticks, that live on the skin of mammals. Hundreds of mite species call the human body home, feeding on flakes of dead skin and oils produced in hair follicles and pores. While the idea of mites living on your body may sound unsettling, they are usually harmless to humans.
What Are Mites?
Mites are arachnids, a class of joint-legged invertebrates that also includes spiders, scorpions, and ticks. There are over 48,000 known species of mites globally, ranging in size from 0.08-3mm. Many mite species live freely in the environment, but others form symbiotic or parasitic relationships with animal hosts.
Mites that associate with mammals are known as acari. The acari mites that inhabit human skin are microscopic – generally measuring between 0.2-0.4mm. They have eight legs and oval bodies. Mites lack wings and antennae. Most species have mouthparts suited for scraping skin and consuming organic debris.
Common Mite Groups on Humans
There are over 65 identified species of mites associated with human skin. The most common mite groups inhabiting humans are:
- Demodex mites – Tiny mites that live inside hair follicles. There are over 100 Demodex mites per square centimeter on an adult’s face.
- Sarcoptes scabiei – Also known as scabies mites. Burrow into skin and cause severe itching.
- Dust mites – Feed on dead skin cells in dust. Main cause of dust allergy.
- Chiggers – Also called harvest mites. Bite skin and inject enzymes that digest skin cells.
- Bird mites – Occur when abandoned bird nests are near a home. Will bite humans.
- Follicle mites – Live in hair follicles, especially eyebrows and eyelashes.
Total Mite Populations on Humans
Researchers estimate that 1 million to 2 million mites inhabit an average adult human body. Newborn babies may have mites transferred from close contact with parents, but mite colonization increases over time. Studies suggest humans acquire 90% of their lifetime mite fauna by age 10.
Mite populations fluctuate seasonally, with higher numbers in summer compared to winter. Mites are most abundant in warm, humid environments. Skin mites prefer to inhabit moist areas of the body.
Body Regions
Mites concentrate in different habitats based on body region:
- Face – Especially eyelashes, eyebrows, nose, and cheeks.
- Upper trunk – Particularly the scalp, neck, and back.
- Armpits
- Pubic area
- Between fingers and toes
Daily Accumulation
Humans lose roughly 1.5 grams of dead skin cells per day. For mites, this accumulated debris is an abundant food source. Hot and humid environments enable larger mite populations to thrive.
Studies suggest each human accumulates the following mite quantities daily:
- 200-300 Demodex folliculorum mites
- 100-200 Demodex brevis mites
- 200-300 Dermatophagoides mites
In total, healthy adults receive 400-800 new acari mites each day. Larger populations accumulate on individuals with oilier skin or those frequently in contact with dust reservoirs where mites propagate.
Mite Habitats on the Body
Different mite species colonize specific microhabitats suited to their biological needs and feeding strategies.
Skin Surface
The surface layer of dead, keratinized skin cells provides an abundant food source for mites. Sarcoptes scabiei mites graze on skin flakes on the surface of the epidermis. The straw itch mite (Pyemotes tritici) also inhabits the skin surface.
Hair Follicles
Many Demodex and follicle mite species reside inside hair follicles where sebaceous glands emit oils and dead skin cells accumulate. Increased sebum production creates an attractive habitat.
Pores
Pores harbor populations of Demodex mites where sebum is readily available. Infested pores may appear enlarged.
Eyelashes
Numerous Demodex mites inhabit the base of eyelashes where oil glands are plentiful. Over 70% of surveyed eyelashes examinated were colonized by mites.
Cryptic Microhabitats
Mites exploit many obscure habitats including skin folds, sweat glands, and mammalian scent glands. Different mite genera inhabit unique niches tailored to their biological requirements.
Do Mites Transfer Between Humans?
Direct and indirect mite transmission occurs between humans. Mites spread through close, direct contact and by dispersing on shed skin cells. Shared pillowcases, towels and other fabrics can harbor mites.
Direct Contact
Humans acquire mites through direct skin-to-skin contact. Newborn babies may receive mites from nuzzling parents. Sexual partners exchange mites, particularly pubic mites like Pthirus pubis. Skin contact sports like wrestling facilitate mite transmission.
Indirect Contact
Mites dispersing from an infested host can survive on fabrics, furniture, and other surfaces long enough to encounter a new host. Scabies mites can survive for 2-3 days detached from humans.
Dust mites and follicle mites transfer on shared bedding, pillows, sofas and clothing. Gym equipment, theater seats and aircraft seats may harbor mites from previous users.
| Transmission Route | Example Mite Species |
|---|---|
| Direct skin contact | Scabies mites, pubic mites |
| Indirect contact via fabrics | Dust mites, follicle mites |
Are Mites on Humans Dangerous?
Most mites coexisting on human skin are harmless or beneficial. But some mite species can cause skin disorders and allergic reactions in certain individuals.
Beneficial Mites
Many common skin mites help decompose dead skin cells, oils, and debris that accumulate on the skin surface. This cleanup service benefits the human host.
Demodex mites may even consume bacteria living in pores that contribute to acne. These mites appear to form a commensal relationship with humans.
Harmful Mites
Mites that bite, sting, or burrow into skin can trigger medical issues:
- Scabies mites – Burrows provoke severe itching and rash.
- Chigger mites – Inject digestion enzymes that destroy skin cells.
- Bird mites – Cause dermatitis and itching when transferred to humans.
- Dust mites – Major cause of allergic reactions to dust.
Overgrowth of Demodex mites in hair follicles may contribute to certain types of folliculitis and skin inflammation. But more research is needed on their pathogenicity.
Infestations
Heavy mite infestations usually only occur when hygiene is very poor. Individuals with reduced mobility, disabilities or neglect may suffer uncontrolled human mite populations leading to dermatitis.
Mite Prevention and Control
While eradicating all mites from your body is impossible, the population size can be minimized through proper hygiene and management. Reduce mites with these prevention tips:
Regular Bathing
Frequent bathing and showering removes dust, dead skin cells, and debris that provide food for mites. Use warm water and gentle cleansers. Wash bed linens weekly.
Reduce Skin Oils
Oily skin promotes mite growth. Use oil-free cosmetic products and cleansers to control excess facial oils. Shampoo regularly to diminish scalp oils.
Avoid Skin Contact Sports
Skin-to-skin sports like wrestling spread mites through direct contact. Avoid sharing uniforms to reduce transmission risks.
Clean Homes
Dust mites thrive in carpets, bedding, and upholstered furniture at home. Vacuum and dust furniture regularly to lower reservoirs. Wash linens in hot water.
Medications
For persistent itching or rashes, see a dermatologist. Scabies, chiggers, and other mites may require prescription medication to eradicate.
Conclusion
Mites are constant yet mostly innocuous companions on the human body. Hundreds of thousands of microscopic mites inhabit our skin, consuming dead cells, oils, and debris. While populations fluctuate over time, healthy adults host ~1 million mites across their bodies.
Most mites appear commensal or beneficial overall, but some species can become invasive pests under certain conditions. Maintaining proper hygiene helps regulate mite populations. If rashes, itching, or other symptoms develop, consult a medical professional for diagnosis and treatment options.