II. Pathophysiology
- Chiggers
- Six-legged larval form of mites (appear as tiny red dots on skin)
- Responsible for Human Bites and vector for disease
- Chiggers crawl onto skin when host sits or lies on lawn or grass (appear as tiny red specks)
- Move into constrictive clothing where they bite
- Trombiculid Mite
III. Associated Conditions: Chigger as vector of disease
- Rickettsial Pox (Rickettsia Akari)
- Scrub Typhus (outside U.S., esp. south asia)
IV. Symptoms
- Pruritic welts along constrictive clothing lines (waist band or sock line)
V. Signs
-
Allergic Reaction to Chigger Bite Saliva
- Large welt forms at site of Chigger Bite
- Bullous Hypersensitivity
- Diffuse bullae may form in response to Chigger Bite
- Distribution of bite sites
- Occluded areas of tight clothing (e.g. beneath waistband, belt line or sock line)
- Intertriginous areas (e.g. axilla)
- Penis may be affected (severe in some cases)
- May be known as Summer Penile Syndrome
- Smith (1998) Pediatr Emerg Care 14(2): 116-8 [PubMed]
VI. Differential Diagnosis
- See Bulla
- See Insect Bite
- See Bullous Impetigo
VII. Management
- See Mosquito Bite
- Symptomatic management
- Antihistamines (e.g. Cetirizine, Diphenhydramine)
- Topical Corticosteroids (high potency)
- Skin hygiene
- Prevent secondary Skin Infection (e.g. at ruptured bullae sites)
VIII. Prevention
- See Prevention of Mosquito Bite
- DEET
- Permethrin treated clothing