Derm

Chigger

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Chigger, Chigger Bite, Mites, Harvest Bug, Red Bug, Trombicula, Summer Penile Syndrome

  • Pathophysiology
  1. Mites
    1. Adult 8-legged Arthopods (Arachnids, same family as Spiders and ticks)
  2. Chiggers
    1. Six-legged larval form of mites (appear as tiny red dots on skin)
    2. Responsible for Human Bites and vector for disease
    3. Chiggers crawl onto skin when host sits or lies on lawn or grass (appear as tiny red specks)
      1. Move into constrictive clothing where they bite
  • Associated Conditions
  • Chigger as vector of disease
  1. Rickettsial Pox (Rickettsia akari)
  2. Scrub Typhus (outside U.S.)
  • Symptoms
  1. Pruritic welts along constrictive clothing lines (waist band or sock line)
  • Signs
  1. Allergic Reaction to Chigger Bite Saliva
    1. Large welt forms at site of Chigger Bite
  2. Distribution of bite sites
    1. Occluded areas (e.g. beneath waistband, belt line or sock line)
    2. Intertriginous areas (e.g. axilla)
    3. Penis may be affected (severe in some cases)
      1. May be known as Summer Penile Syndrome
      2. Smith (1998) Pediatr Emerg Care 14(2): 116-8 [PubMed]
  • Management