American Medical Association Family Medical Guide - American Medical Association [648]
Lice
Lice are tiny, wingless insects that can live on any part of the body and suck blood from the skin. The eggs of lice, known as nits, look like tiny white grains that cling to the hair. Infestations of body lice are rare and can be transmitted through close physical contact and by sharing infested cloth-ing, towels, or bedding. Crab lice, or pubic lice (see page 485), live in pubic hair and are usually spread through sexual contact. Head lice infestations most often occur among schoolchildren. If your child has lice, report it to his or her school. Lice infestations are considered a public health problem, and it is necessary to trace them to their source to prevent them from spreading more.
Louse (magnified)
Symptoms
The symptoms of a lice infestation include intense itching at the site of infestation, a feeling of something moving through the hair, and slight redness to severe inflammation of the skin caused by an allergic reaction to the bites. Lice bites pose a slight risk of infection.
Diagnosis and Treatment
If you have lice on your scalp or another part of your body, your doctor will recommend treating the affected area with a shampoo or lotion that contains permethrin. Carefully follow the instructions on the package. Then, using a fine-toothed comb or tweezers, remove as many nits as possible. Spray surfaces with a furniture spray that contains permethrin. Wash clothing, bedding, and towels in hot water, and dry them in a hot dryer. If possible, iron them. If any items cannot be cleaned, store them in a plastic bag for at least 2 weeks.
If lice are present on another part of your body, such as the genitals, inform your sex partner or anyone else with whom you have had close physical contact so he or she can also seek treatment.
Fleas
Fleas are tiny, wingless insects that live on and bite animals but that also can bite people. There are many species of fleas, and each one is a parasite of a different animal. Flea eggs hatch in animal bedding about 7 days after they are laid. The fleas live in the bedding and feed off their hosts. Fleas do not stay long on the skin.
Flea (magnified)
Flea infestations of humans are most common in developing countries and in places with crowded living conditions, close contact between people and domestic animals, or unclean conditions. Fleas can spread life-threatening diseases such as plague (see page 31).
Symptoms and Treatment
Isolated flea bites on the skin can cause a rash and intense inflammation (see page 126) for up to 2 days. If you suspect a flea infestation in your bedding, furniture, or rugs, spray the items with a flea pesticide or repellent. If the infestation is extensive and you are not able to eliminate the fleas, call a professional exterminator. To avoid flea infestations, use antiflea spray, powder, or shampoo on your pet, and spray pet bedding regularly. Flea collars for pets also can be helpful. Apply an insect repellent before going into a flea-infested area.
Chiggers
Chiggers (sometimes called red bugs or harvest mites) are a type of mite that lives in grasses, shrubs, and vines. Farmers, hikers, hunters, and others who spend time outdoors are most likely to get chigger bites. The larva (or immature mite) is barely visible inch). It attaches to a hair follicle in an area of skin that is thin and moist (usually around the ankles, groin, or waistline), or wherever clothing is tight. The larva releases enzymes that dissolve the skin and then eats the liquefied cells. It feeds for 1 to 4 days in one spot and then drops off.
Symptoms
The most common symptom of chigger bites is intense itching in the affected area, especially at night. Some people may have an allergic skin reaction, such as hives (see page 1066) or an itchy, red, pimplelike lump. In some cases, blisters, swelling, or large red patches