Bed bugs, chiggers, fleas or dust mites: what's biting you?

House dust mites live in beds, upholstered furniture and carpet, where they feed on skin flakes shed by people and pets. They aren't parasites, and they can't bite or sting.^2-3

What they can cause is an allergy: a stuffy or runny nose, sneezing, coughing, watery eyes and, in some people, asthma. Kentucky's entomologists say an allergist can confirm a dust mite allergy with a skin or blood test.²

So if you have itchy welts, something else is the cause. Spraying won't fix dust mites either. Washington State University recommends no pesticide for them, and suggests vacuuming mattresses, furniture and floors, washing bedding in hot water, lowering the humidity and using mattress encasements.³

• When: bed bugs usually bite at night while you sleep, and the bite is painless.⁴
• Where: any skin left uncovered in bed, such as the face, neck, shoulders, back, arms and legs.⁴
• What you see: many people get an itchy red welt within a day or so. Others have little or no reaction, and sometimes it shows up days or weeks later. In studies in infested apartments, about 30 percent of people didn't react even when bitten again and again.⁴
• Clues: Kentucky's entomologists say to suspect bed bugs if you wake up with itchy welts you didn't have at bedtime, or if the bites started after travel or after bringing home a used bed or furniture.⁴
• How to confirm: find the bugs, their shed skins or the dark spots they leave on mattresses and box springs. That can be hard early on, and it often takes a professional.^{1, 4}

• What they are: chiggers are the larvae of a mite, about the size of a grain of sand. They live outdoors in tall weeds and damp, overgrown places, mostly in summer.⁵
• Where: they attach where clothing fits tight, such as the ankles, waistline and armpits.⁵
• What you see: hard, raised red bumps that start itching within 24 hours and can itch for a week or more. Since the itching starts later, people often don't connect it with being outdoors the day before.^{1, 5}
• What they don't do: chiggers don't burrow into skin or suck blood, and Kentucky's entomologists say no diseases are associated with chiggers in the US.⁵
• Where to look: in the yard, not the house. Mowing often and clearing tall grass, shrubs and weeds is what cuts chiggers down.⁵

Flea bites usually show up around the lower legs and ankles as small, hard, red, itchy welts. Fleas mostly come with pets, though mice, rats, squirrels, opossums and raccoons can bring them too. You can confirm them by checking your pets, setting a flea trap, or walking the house in white socks pulled up high, where fleas show up easily.¹ Flea foggers: what they do and what works instead covers getting rid of them.

Kentucky's entomologists list these too:¹

• Bird and rodent mites. Mites from birds nesting on the house or from mice and rats can bite people, often after the animals leave or die. Most mites that bite people indoors are big enough to see as dark, slow-moving specks.
• Scabies. A mite too small to see that burrows into the skin. It spreads only through close personal contact or sharing a bed, a doctor diagnoses it, and the house doesn't need treating.
• Spiders. Most are harmless, and bites are rare. A spider bite is hard to identify from the mark alone unless someone saw the spider bite.
• Ticks, mosquitoes and biting gnats. Ticks and mosquitoes can also cause a reaction that shows up later. Biting gnats, also called no-see-ums, breed outdoors in wet places and are so small they often go unnoticed.
• No pest at all. Many bite-like reactions come from soaps, detergents, cleaners and other household products.

Kentucky's entomologists say no pesticide should go down unless biting pests or clear signs of them turn up. If an inspection finds none, they point people to a dermatologist or another professional instead.¹

A pest control company can inspect for bed bugs and fleas and treat for them once it finds them. What bed bug treatment costs has the published price ranges, and How to check a pest control company's license links each state's license lookup. You can also get quotes from pest control companies near you.