Scabies Health Dictionary

A skin infestation caused by the mite SARCOPTES SCABIEI, which burrows into the skin to lay eggs. Scabies is highly contagious by close physical contact and is most common in infants, children, and young adults.

The mite’s burrows appear on the skin as grey, scaly swellings, usually between the fingers, on the wrists and genitals, and in the armpits.

Later, reddish lumps may appear on the limbs and trunk.

The infestation causes intense itching, particularly at night.

Treatment is with an insecticide lotion.

Sarcoptic infestation of the human skin particularly a contagious skin disease caused by invasion of the epidermis

A parasitic skin diseases caused by the mite, Sarcoptes scabiei, presenting often as intensely itchy papules, vesicles, or tiny linear burrows containing scabies mites and their eggs. Lesions are often found around finger webs, skin folds and flexures, the abdominal region and external genitalia (especially in men). Often associated with a rash on the body, but usually sparing the face.

A common contagious itching disease caused by Sarcoptes scabei hominis (see SARCOPTES) which can live only on human skin. The fertilised female burrows into the skin surface, creating a tunnel within the stratum corneum in which she deposits 2–3 eggs per day, as well as faecal pellets which contain the ALLERGEN which initiates the immune reaction responsible for symptoms. The adult female is just visible. Eggs hatch within 3–4 days, producing larvae. After successive moults these become adult mites and the 15-day lifecycle re-starts. A rapid build-up of mite numbers is not noticed by the host until an immune response induces itching after about six weeks. Subsequently, scratching reduces the adult mites to a dozen or fewer. Scabies is spread by skin-to-skin contact, usually via the hands: it thus spreads in a family or sexual setting. Though most common in young adults, scabies can affect any age-group.

Typically the patient complains of widespread severe itching, worse when the body is warm after a bath or in bed. Burrows are visible as wavy black lines 3–5 mm long in the skin of the hands, wrists or sides of the feet. The intensity of the rash depends on the immune response. Papules, pustules, crusts and excoriations are seen on the hands and there may be a widespread eczematous (see DERMATITIS) or urticarial (see URTICARIA) rash elsewhere. Papules or even nodules on the PENIS and SCROTUM are characteristic. In infants, burrows occur on the palms and soles. Diminished immune response in old age, DOWN’S (DOWN) SYNDROME, etc. lead to a type of scabies which is less itching and more scaly. Rarely, absence of immune response causes a mite-saturated, generalised scaly dermatitis (Norwegian scabies). Admission of such a patient to hospital may result in an outbreak of scabies in other patients, sta? and visitors caused by mite-infested airborne scale.

Treatment MALATHION 0·5 per cent aqueous lotion, or PERMETHRIN 5 per cent cream, applied to the whole body, except the head, for 24 hours and then washed o? cures the infection. In infants the head and neck should be included. The secondary eruption may take 2– 3 weeks to settle completely and 10 per cent crotamiton cream is used during this period. It is essential that all intimate contacts be treated simultaneously. FOMITES need not be treated.

n. a skin infection caused by the mite *Sarcoptes scabiei. Scabies is typified by severe itching (particularly at night), red papules, and often secondary infection. The female mite invades the skin to lay her eggs and the newly hatched mites pass from person to person by close prolonged contact. The intense itching represents a true allergic reaction to the mite, its eggs, and its faeces. Commonly infected areas are the penis, nipples, and the finger webs. Treatment is by application of a scabicide, usually *permethrin or *malathion, to all areas of the body from the neck down; benzyl benzoate may be used but is more irritant. All members of a family need treatment, but clothing and bedding need not be disinfested.