Mites cause a great deal of discomfort and stress for a microscopic pest. An excellent resource for understanding the sources of itches of unknown origin (that may or may not include mites) is INVISIBLE ITCHES: Insect and Non-Insect Causes from the University of Kentucky.
The first step to combating mites is to attempt a definitive diagnosis. Seek medical attention when exposure to mites is suspected as the cause of skin irritation. This is certainly true in the case of scabies infestations that will require medication.
The county of San Diego offers an excellent summary of the various species of mites that affect humans.
Northern Fowl Mite: This mite is commonly found on domestic birds, pigeons and many wild birds. It produces several generations each year and can live away from a host for 2-3 weeks. When there are not any birds, these mites will bite humans causing dermatosis, which makes skin itchy and red. This mite can also become a household pest when birds build nests around the outside of a home, such as the eaves or in attics.
Tropical Rat Mite: This mite is found on rats and in their nests. It is gray to pale-yellowish gray and changes color to red or black when swelled up with blood. This mite can grow from an egg to an adult in anywhere from 6-12 days. It can live up to 63 days without feeding. This mite will bite humans when rats are not around and can cause dermatitis. Preventing rats from entering the home is the best protection against this mite.
Chicken Mite: This mite feeds on poultry, pigeons, sparrows and other birds. When they have not eaten they are white, but after a blood meal they turn bright red. The females lay their eggs in cracks and crevices inside poultry houses or in bird nests. They can grow from egg to adult in as little as one week. An adult can survive without a blood meal for 4-5 months. Chicken mites hide in dark places during the day and look for a blood meal at night.
Itch or Scabies Mite: These mites tunnel into the skin, especially on hands and wrists. Sores burst turn into scabs. Itching is intense and known as ‘scabies.’ Scratching can cause bleeding and infection. Most often you get them by direct contact with an infected person, not an animal. See your doctor right away for control of Scabies. PEST CONTROL PROFESSIONALS DO NOT TREAT SCABIES.
Dust Mites: Dust mites can be found in house dust all over the world. They live in bedding, couches, carpet, stuffed toys and clothing. They feed on the dead skin that falls off humans and animals. Some people are allergic to dust mites, but most are not. Dust mites are more common in areas with high levels of humidity. PEST CONTROL PROFESSIONALS DO NOT TREAT FOR DUST MITES.