Skin inflammatory (nontumor)
Infestations
Scabies (mite)


Topic Completed: 1 July 2011

Revised: 3 September 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Scabies[TI] mite[TI]

See Also: Penis & scrotum chapter

Mowafak Hamodat, M.B.Ch.B., M.Sc.
Page views in 2018: 3,420
Page views in 2019 to date: 3,195
Cite this page: Hamodat M. Scabies (mite). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumorscabies.html. Accessed October 14th, 2019.
Definition / general
  • Mite that produces burrows and extremely pruritic erythematous papules on interdigital skin, palms, wrists
Pathophysiology
Diagrams / tables

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Life cycle

Case reports
Treatment
Microscopic (histologic) description
  • Burrow containing mite body parts appears as cleft in upper epidermis
  • Epidermis exhibitis acanthosis, parakeratosis, spongiosis, with dense eosinophilic dermal infiltrate
  • In the dermis, there is superficial perivascular and sometimes diffuse infiltrate of lymphocytes and histiocytes, sometimes accompaned by neutrophils and less often eosinophils
  • In nodular skin lesions, the dermal infiltrate may be very dense and atypical and hyperchromatic cells may be evident, in addition to histiocytes, plasma cells, eosinophils and lymphocytes
  • Mites (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 531 [Accessed 29 August 2019]):
    • Male mites range in size from 213 - 285 μm long by 162 - 240 μm wide
    • Female mites range from 300 - 504 μm long to 230 - 420 μm wide
    • Sarcoptes are round to ovoid when viewed from the back; when viewed from the side they are ventrally flattened and dorsally rounded (similar to a turtle)
    • They possess short stumpy legs and have no internal or external respiration apparatus (stigmata or tracheae)
    • Ventral surface contains a number of chitinized plates called apodemes, the dorsal surface is partially covered by wide angled, V shaped spines
    • Cuticular surface is sculptured into numerous parallel ridges which superficially resemble human finger prints and the anus is at the posterior end of the mite
    • The last segment (tarsus) of legs 1, 2 and 4 on males and legs 1 and 2 on females has a long, unjointed empodium or stalk with a small sucker-like pad at its end
      • These stalks are diagnostic for Sarcoptes
Microscopic (histologic) images

Contributed by Bobbi Pritt, M.D.

Sarcoptes scabei var. hominis: mites, eggs and fecal pellets (scybala)



Contributed by Dr. Daniel Ostler



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Mite

Videos

Sarcoptes scabei var. hominis

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