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These are bites caused by head lice, a parasite that is easily passed to and fro by direct contact between people. It is especially common in children, and can be passed through the sharing of hats, combs, and other materials that come in contact with the head (even couches).
The first symptom usually noticed by someone infested with lice is itching, which is actually caused by your body having an allergic reaction to the bites. A tickling feeling may also be present due to the moving adults, as well as sleeplessness. Excessive scratching leads to sores on the head and/or neck, and the open wounds can lead to secondary infection. The parasites are not considered hazardous to your health since they do not spread disease.
Misdiagnosis is extremely common when it comes to lice, partly due to the observed mistaking dandruff or other particles for nits. The scalp must be examined and the adults, nymphs, or egg masses ("nits") have to be discovered for a correct diagnosis to be made. However, these can usually be seen with the naked eye. If there are no adults or nymphs seen, and the nits are not close to the scalp, treatment will usually not be necessary.
The treatment procedures for lice would really better be described as eradication procedures. Over the counter remedies are readily available, usually in bottles that are applied directly to the scalp and hair. Then, the a special nit comb is used to remove the dead lice and nits. In a pinch, a flea comb made for a cat or dog can also be used. Generally, an infestation can be eliminated in less than a week and a half. Retreatment or approximately the ninth day is a recommended step to be sure that every last louse is gone. Though lice do not live long when separated from a host, it is suggested that additional steps are taken, such as washing virtually everything that the infected person came in contact with. This includes clothing, bedding, combs, and brushes. Cloth items can also be stored in plastic bags for two weeks, at which time all lice should be dead. Vacuuming of furniture and floors is also suggested.
As with most parasites, writing this post made my skin crawl.
Source is the Center for Disease Control and Prevention.