Scabies

Scabies, also known as the itch, is a contagious ectoparasite skin infection characterized by superficial burrows and intense pruritus (itching). It is caused by the mite Sarcoptes scabiei. The word scabies itself is derived from the Latin word for "scratch" (scabere). Other names or variants of the condition include Mite, Itch Mite, Mange, Crusted Scabies, Norwegian Scabies, Sarcoptes scabiei, or The Seven-Year Itch.

The characteristic symptoms of scabies infection include superficial burrows, intense pruritus (itching), a generalized rash and secondary infection. Acropustulosis, or blisters and pustules on the palms and soles of the feet, are characteristic symptoms of scabies in infants.^[1]

S-shaped tracks in the skin are often accompanied by small, insect-type bites called nodules that may look like pimples. These burrows and nodules are often located in the crevices of the body, such as the webs of fingers, toes, feet, buttocks, elbows, waist area, genital area and axilla, and under the breasts in women.

The intense itching and rash characteristic of scabies infection is caused by an allergic reaction of the body to the burrowed microscopic scabies mites. The rash can be found over much of the body, especially in immunocompromised people (HIV positive or elderly); the associated itching is often most prevalent at night.

Secondary infection of impetigo, a Streptococci or Staphylococci bacterial skin infection, after scratching. Cellulitis may also occur, resulting in localized swelling, redness and fever (DermNet).

In immuno-compromised, malnourished, elderly or institutionalized individuals, infestation can cause a more severe form of scabies known as crusted scabies or Norwegian scabies. This syndrome is characterized by a scaly rash, slight itching and thickened crusts of skin containing thousands of mites. Norwegian scabies is the form of scabies that is hardest to treat.

In individuals never before exposed to scabies, the onset of clinical signs and symptoms is 4–6 weeks after infestation, some people may not realize that they have it for years; in previously exposed individuals, onset can be as soon as 2–4 days after infestation.