Jeffrey Hahn, Asst. Extension Entomologist
A common call that has been received recently has been from people that have been experiencing bites of an unknown source. It is challenging to correctly diagnose these problems. It is important to know that unknown bites can be the result of insects as well as non-insect causes. If it is an insect infestation, the most common causes are bed bugs and fleas.
Bed bugs have been on the increase over the last 10 or so years. Adult bed bugs are about 1/4 inch long, brown, and similar in size and shape to wood ticks; newly hatched bed bug nymphs are about 1/16th inch long or about the size of a pinhead. Bed bugs like to hide during the day and generally prefer to bite at night so it's possible to be bitten and not realize it. When looking for bed bugs, first check out bed rooms and other places where people sleep or rest. Other good areas to look are places where luggage is stored.
Bed bugs like to hide in cracks and behind or under objects so examine closely around mattresses, boxsprings, bed frames, as well as dressers, desks, chairs, and other furniture, the edges along carpeting and behind clocks, pictures, and baseboards. Also be aware of signs of bed bugs in your home. In addition to bites, watch for cast skins (empty shells of insects) as well as dark (but not red) spots. These spots are fecal droppings, composed of digested blood. Look for these spots on sheets, bedding, or other places where bed bugs feed or around their hiding places.
You can also try to determine whether bed bugs are present by using a bed bug interceptor. They are small plastic trays with an inner and outer ring. Put them under each leg of your bed. Bed bugs that attempt to climb up from the floor to the bed become trapped in the outer well. Any bed bugs that try to climb down will become trapped in the inner well. You can purchase Bed bug Interceptors online (type "bed bug interceptor" into a search engine for sources).
regardless of whether you have pets or not. An adult flea is small, about 1/8th inch long and dark colored. It's body is flattened from side to side and it has long back legs for jumping. Because of their size and shape, they can easily hide in cracks and crevices and not be seen.
To determine whether you have fleas infesting your home, try the white socks test. Walk slowly through a room where you suspect fleas wearing a pair of white socks. Fleas are attracted to the vibrations from the walking and the warmth of the person and will jump towards the ankle. Their dark colored bodies show up plainly against the white background of the socks. Particularly check areas where pets spend a lot of time (if they are present).
While bed bugs and fleas are the most common biting insects there are other possible causes. Head lice, mosquitoes, as well as insect relatives, such as bird mites, like northern fowl mites, chiggers, and rodent mites, such as tropical rat mites, can potentially be problems. During winter however, mosquitoes, bird mites and chiggers are not active and are not possible causes. Head lice are most common on children and are restricted to the head (it is possible to find body lice which are located on the body as well as clothing and bedding. However, they are rarely a problem). Rodent mites can be encountered, although this rare. In one case, a tropical rodent mite problem was infesting a pet guinea pig and was biting the people in the house. Dust mites do not bite people; they are problem because of the allergic reactions to them by individuals.
If you are not clear whether you have an insect or mite problem in your home, consider having an experienced pest control company inspect your home. You could also submit any suspicious insects to your local county extension office for identification. Under no circumstances should you use insecticides in your homes if you can not confirm a biting insect or mite problem.
However, if you do not find any evidence of biting insects or mites, it is very important to consider non-insect explanations. There are a variety of causes that can explain insect-like bites or irritations that are unrelated to insects or mites. Some of these possibilities can include dry air, allergic reactions to personal or household products (e.g., detergents, soaps, cosmetics, clothes, jewelry), environmental contaminants, microscopic fibers (e.g. insulation or paper fibers), certain health conditions (e.g. diabetes, neurological, liver, or kidney disorders), or even stress.
There is also a condition known as delusory (or delusional) parasitosis, also called Ekbom's syndrome. This is a very real condition where sufferers have the mistaken belief that they are being invaded by parasites even when presented with evidence to the contrary. Typically, people suffering from delusory parasitosis have been battling this problems for months, sometimes even years. Commonly they have had pest control technicians search their homes for pests but without find anything that would be biting. They often have tried a variety of solutions, including pesticide applications, but if there is any relief it is short-lived. Some sufferers have even thrown out their furniture, even moved, to tried to escape this problem. Of course this action is not successful.
People that are experiencing unknown bites that can not confirm an insect or mite problem should see a family physician for help in diagnosing their problem. They should work with an entomologist to verify or rule out insects. For more information on unknown bites and delusory parasitosis see the following web pages, http://www.ca.uky.edu/agc/pubs/ent/ent58/ent58.pdf http://delusion.ucdavis.edu/delusional.html and http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7443.html