Insect Bite

Aka: Insect Bite, Stinging Insect, Arthropod Bite, Arthopod, Arachnid, Insect, Arthropod Dermatosis, Bug Bite

1. See also
   1. Allergic Reaction
   2. Stinging Insect Allergy
   3. Bee sting
   4. Mosquito Bite
   5. Chigger Bite
   6. Flea Bite
   7. Bed Bug
   8. Tick Bite
   9. Spider Bite
   10. Scorpion
   11. Vector Borne Disease
2. Pathophysiology: Arthropod types
   1. Arachnids (8 legs)
      1. Spiders
         1. See Spider Bite
         2. Black Widow Spider (Lactodectus mactans)
         3. Brown Recluse Spider (Loxosceles reclusa)
         4. Precautions
            1. "Spider Bites" are typically not due to Spiders, but rather other causes (e.g. MRSA Cellulitis)
            2. Most Spider Bites are benign (not black widow or brown recluse)
               1. Need only minimal local therapy (Wound Cleansing, cold therapy)
      2. Mites
      3. Ticks
         1. See Tick Bite
         2. See Vector Borne Disease
   2. Insects (6 legs) - Hexpoda subphylum
      1. Diptera (2-winged Insects)
         1. Mosquito
         2. Gnats
         3. Flies
         4. Midges
3. Signs
   1. Most "Spider Bites" are due to some other cause
   2. Pruritic, Red Papules
      1. Typical Insect Bite (e.g. Mosquito Bite or biting midge such as no-see-ums, Sand Fly)
   3. Pruritic welts along constrictive clothing lines (waist band or sock line)
      1. Chigger Bite
   4. Clustered or linear Papules at the ankles
      1. Flea Bite
4. Differential Diagnosis
   1. Folliculitis
   2. Impetigo or Cellulitis
   3. Shingles
   4. Contact Dermatitis
5. Complications
   1. Anaphylaxis or other serious Allergic Reaction
   2. Papular Urticaria
   3. Vector Borne Disease (e.g. Lyme Disease with Erythema Migrans)
   4. Cellulitis
      1. Inflammation out of proportion to Insect Bite
      2. Regional Lymphadenopathy
      3. Ascending lymphangitis
6. Management: General
   1. Remove Stinger with forceps (avoid pinching the Stinger gland)
   2. Apply ice pack for 10-20 minutes per hour for 3 hours
      1. Contraindicated in Tarantula Bite
   3. Treat itch symptomatically
      1. Oral Benadryl for nighttime itch, Zyrtec for daytime itch
      2. Cool compresses
      3. Oral Analgesics (e.g. Acetaminophen or NSAIDs)
      4. Anti-irritant agents (e.g. sarna)
      5. Protective agents (e.g. calamine)
      6. Topical Corticosteroids (low potency such as 1% Hydrocortisone, brief use) may be considered
      7. Avoid topical Antihistamines (e.g. topical Benadryl) due to Contact Dermatitis risk
7. Management: Acute Allergic Reaction
   1. See Anaphylaxis
   2. See Stinging Insect Allergy
   3. Prescribe Epi-Pen for emergency use for those with Anaphylaxis history
8. Management: Suspected Cellulitis
   1. See Cellulitis for antibiotic selection
   2. Tetanus Prophylaxis
9. Prevention
   1. See Prevention of Vector-borne Infection
   2. Check clothes for Insects before donning
   3. Avoid habitats
      1. Woodpiles
      2. Crawl spaces
      3. Corners of buildings
   4. Dress for working outdoors
      1. Keep skin covered by clothing
         1. Wear gloves
         2. Shirt tucked into pants
         3. Pants tucked into socks
         4. Wear a hat and high collar
         5. Avoid loose clothing
      2. Avoid Insect attractants
         1. Bright colors
         2. Perfumes
   5. Insect Repellants
      1. DEET (<30% is safe in young children)
         1. Mosquitoes
         2. Fleas
         3. Gnats
         4. Chiggers
      2. Permethrin (Elimite, Nix) on clothes
         1. Ticks
10. References
    1. Norris (1998) Physician and Sports Med 26(7):47-58
    2. Juckett (2013) Am Fam Physician 88(12): 841-7 [PubMed]
    3. Kemp (1998) Postgrad Med 103(6):88-106 [PubMed]