Basically, scabies is a transmissible skin infection caused by a certain type of mite (Sarcoptes scabiei) that causes burrows on the skin, extreme itching, and secondary infection.

The skin mite produces intense, itchy skin rashes when the impregnated female tunnels into a layer of skin and deposits eggs in the burrow. Once the eggs are hatch, between 3 to 10 days, the larvae move about on or within the skin, molt into a nymphal stage, and then mature into adult mite where they live on the skin for 3 to 4 weeks. All of these development causes further allergic reactions and itching.

Scabies are transmitted mainly through skin-to-skin contact with an infected person. With that in mind, skin mites can be transferred through sexual contact.

It takes about 4 to 6 weeks to develop symptoms of scabies after initial infestation. This means that person may have passed scabies to anyone whom they had close contact at that time when the symptoms are not too obvious.

The symptoms are caused by an allergic reaction that the body develops over time because of the mites and their by-products under the skin. There are usually relatively few mites (around 11) on a normal, healthy person. Scabies are microscopic although sometimes the mites are visible as a pinpoint of white.

The females burrow into the skin and lay eggs, while the males usually roam on top of the skin, although they can and do occasionally burrow. Both males and females surface at times, especially at night. Mites can be washed or scratched off the skin to keep the population low, although this does not guarantee a cure. In scratching the skin, make sure to use a washcloth to avoid cutting the skin as this can lead to further infection. Humans also create antibodies to the scabies mites that do kill some of them.

The skin burrows appear as fine, wavy and slightly scaly line a few millimeters to one centimeter long. A tiny mite may sometimes be seen at the end of the burrow. Most burrows can be found in the webs of fingers, flexing surfaces of th wrists, around elbows, armpits, the areolae of the female breasts and on male genitals, along the belt line, and on the lower buttocks.

Scabies is frequently misdiagnosed as intense itching before the papular eruptions form. Upon initial eruption, the burrows appear as small, barely noticeable bumps on the hands and may be slightly shiny and dark in color rather that red. The itching may not exactly correlate to the location of these bumps. As the infestation progresses, these bumps become more red in color.

General diagnosis is made by finding the burrows, which often may be difficult because they are scarce and obscured by scratch marks. If these burrows are not found in the primary areas known to be affected, the entire skin surface should be examined.

The suspicious area can be rubbed with ink from a fountain pen or a topical tetracycline solution that would glow under a special light. The surface is then wiped off with an alcohol pad. If the person is infected with scabies, the characteristic zigzag or S pattern of the burrow across the skin would appear.

When a suspected burrow is found, diagnosis may be done by microscopy of surface scrapings, which are placed on a slide in glycerol, mineral oil, or immersion in oil and covered with a coverslip. Avoiding potassium hydroxide is necessary because it may dissolve fecal pellets. Positive diagnosis is made when the mite, ova, or fecal pellets are found.