The flea we come into contact with most commonly is the flea that feeds on your dogs and cats. In the past, when more people lived on farms, the pig flea had the greatest affinity for humans. Unlike lice, fleas are not interested in living on you; they visit you for a blood meal, and drop back off around the house. Flea shampoos may be dangerous, and are not necessary to control fleas.
Most flea shampoos designed for pets employ an insecticide as the active ingredient. These same insecticides are used on humans to control head lice. The two most common insecticides used in flea shampoo are pyrethrin and permethrin, reports the Univeristy of California. The other insecticide found in human shampoos for crablouse infestation is lindane. All these agents kill fleas.
Using the Shampoo
Flea or lice shampoo, when used at all, should be used with great caution. Even transient contact with the skin causes a degree of absorption. Wash hair in a basin to prevent shampoo contact with any other parts of the body. Rinse quickly and thoroughly after application. Within half an hour, all fleas or lice should be dead. Then wash thoroughly with a non-toxic shampoo, combing the shampoo through the hair before rinsing. While it is unlikely that fleas have left eggs in the scalp, pyrethrin and permethrin do not kill eggs, and a comb will remove them.
Toxic and Allergenic
Flea shampoos that employ pesticides are toxic and sometimes allergenic to you and your pets. Because your pets have coats over their whole bodies, fleas can inhabit them by moving around between blood meals. For humans, this is more difficult, because a simple combing will cause fleas to jump off the scalp. Lice, however, do inhabit the scalp, and flea shampoos are effective against them. Do not use fleas shampoos or lice shampoos on children without consulting a physician.
If fleas are the only problem, consider alternatives to pesticide shampoos. Aromatics repel fleas, so the use of mint, citronella or strong lemon with shampoo sets up an aromatic barrier against fleas attacking your scalp.
In Addition to Shampoo
Shampoos address only a fraction of the problem. If you are bitten by one flea, there are hundreds more in the general environment, each laying eggs at a rate of 60 a day. These eggs hatch every 90 days, ensuring a steady and increasing supply if left untreated, according to the Earth Easy website. Measures to control environmental fleas include washing all bedding in hot water, dusting the carpets with a flea powder and then vacuuming several times to remove dead fleas and eggs. A night light over a dish of soapy water near your pet's bed will attract and drown adult fleas. Diatomaceous earth is a natural product that controls fleas by leaving it in the environment, for example, on pet bedding.