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Trombiculidae (chigger mite)
Epidemiology:
1) normally feed on mice in grassy or brush-covered sites in tropics
2) Trombiculid mites are vectors for transmission of the etiologic agent of scrub typhus in tropical & subtropical parts or Asia
Pathology:
1) larvae attach themselves host & pierce the skin of host with stylostome
2) saliva may produce large wheal & flare reactions with intense pruritus
3) scratching invariably destroys the body of a mite attached to a person
4) lesions vesiculate & form a hemorrhagic base
Clinical manifestations:
1) itching & burning lasts for weeks
2) rash is most common areas of skin where clothing restricts movement of mites (ankles, waistline, armpits & wrists)
3) erythematous, excoriated papules, occasionally with central punctum
Laboratory:
- larvae are 6-legged, often red in color
Management:
1) antihistamines reduce pruritus
2) topical steroids reduce pruritus
3) camphor & menthol lotion [3]
General
acarus (mites, ticks)
Properties
KINGDOM: animal
PHYLUM: arthropod
ORGANISM-CLASS: arachnid
References
- Clinical Diagnosis & Management by Laboratory Methods,
19th edition, J.B. Henry (ed), W.B. Saunders Co.,
Philadelphia, PA. 1996, pg 1306
- Harrison's Principles of Internal Medicine, 13th ed.
Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 935
- Medical Knowledge Self Assessment Program (MKSAP) 15,
American College of Physicians, Philadelphia 2009