Parasitic Diseases: Scabies

Sarcoptes scabieie is known as the “itch mite.”  It is an oval, flattened mite with dorsal spines.  On exposure the mite burrows into the skin and deposits eggs in the outer layers (stratum corneum).  It affects families and communities world wide, but is most commonly found in children, young adults and the elderly.  It is prevalent where there is poverty or overcrowding, institutional care (nursing homes), refugee camps, patients with immune deficiencies, and areas where medical care is limited, thus delaying the diagnosis and treatment.

Above are two sisters that have spread the mite between each other.  Secondary infections with scabies is common.  These two children also developed secondary impetigo resulting in the yellow crusting you see in the images.  The axillary regions are frequently involved.

Other sites of predilection include the finger webs, wrists, areolae, umbilicus, lower abdomen, genitals and buttocks.  Papular lesions and “burrows” are typical.  Some lesions may become nodular and are referred to as nodular scabies.

Scabies is nearly always acquired by skin-to-skin contact between individuals infested with scabies and those that are not.  Typically several mites infest upon exposure and after mating the male mite dies.

The female mite burrows into the outer skin layers and lays up to 3 eggs each day for her lifetime of one to two months.  The eggs develop into adult mites within 10-14 days.

The various clinical forms of scabies include nodular, Norwegian or crusted and sexually transmitted forms–genital.

TREATMENT:  A variety of topical treatments are available to include permethrin, lindane, benzyl benzoate combined with 10% precipitated sulfur in white petrolatum, Tinospora cordifolia lotion and topical ivermectin have all been shown effective.  In addition, oral ivermectin is also very effective.  To read more about scabies click HERE.  For those curious about seeing more images of the scabies mite and what it does in the skin click HERE.