Derm

Mosquito Bite

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Mosquito Bite, Mosquito

  • Pathophysiology
  1. Mosquitos are a type of biting Diptera (2 winged Insect)
    1. Includes Flies, Gnats, Midges
  2. Bite conditions
    1. Attack exposed skin
    2. Active during cooler times of day, and out of sun
  3. Disease Vector
    1. Malaria
    2. Yellow Fever
    3. Dengue Fever
    4. Rift Valley Fever
    5. EncephalitisArboviruses
      1. California (including LaCrosse) Encephalitis
      2. Saint Louis Encephalitis
      3. Eastern equine Encephalitis
      4. Western equine Encephalitis
      5. West Nile Virus Encephalitis
      6. Japanese Encephalitis
  • Signs
  • Local reaction
  1. Phase 1:
    1. Immediate wheal forms at bite site
    2. Reaction to:
      1. Histamine in insect Saliva
      2. IgE-mediated reaction to insect Saliva
  2. Phase 2:
    1. Erythematous Papules follow in 2-6 hours
    2. Local swelling
    3. Intense Pruritus
  • Management
  1. Oral Antihistamines
  2. Cold packs
  3. Calamine lotion
  4. Zyrtec (10 mg qd)
    1. Reduces Pruritus and post-bite Papule
    2. Active for up to 12 hours after taking dose
  5. Topical anesthetic or Antihistamine
    1. AVOID repeated use
    2. May result in Allergic Contact Dermatitis
  6. Topical Corticosteroids
    1. Slower response compared with other topicals
    2. Beware associated atrophy
      1. Avoid on face and intertriginous areas
      2. Use mild preparations
  7. Homemade remedies (unknown efficacy)
    1. Apply Toothpaste or baking soda paste to area
  • Prevention
  1. See Prevention of Mosquito Bite
  2. Highly effective prevention in Mosquito exposure
    1. N,N dethyl-m-toluamide (DEET, under 30%)
    2. Permethrin
      1. Spray clothes and bed netting only (not skin)
      2. Permethrin remains despite several washings
      3. Very effective in combination with DEET
  3. Ineffective agents in preventing Mosquito Bites
    1. Vitamin B1
    2. Citronella