Emergency Medicine Book


Insect Bite

Aka: Insect Bite, 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
        1. Scabies
        2. Chiggers
      3. Scorpions
      4. Ticks
        1. See Tick Bite
        2. See Vector Borne Disease
    2. Insects (6 legs)
      1. Diptera (2-winged Insects)
        1. Mosquito
        2. Gnats
        3. Flies
        4. Sand Flies
        5. Midges
      2. Siphonaptera
        1. Fleas
      3. Hemiptera ("true bugs")
        1. Bed Bugs
      4. Psocodea
        1. Lice
      5. Hymenoptera (includes Stinging Insects)
        1. See Stinging Insect Bite
        2. Apidae (Bees)
          1. Honey bees
          2. Bumble bees
        3. Vespidae
          1. Wasps
          2. Yellow Jackets
          3. Hornets
        4. Formicidae (Stinging Ants)
  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: Insect Bite Reaction
    1. See Annular Lesion
    2. See Stinging Insect Reaction
    3. Folliculitis
    4. Impetigo
    5. Cellulitis
    6. Shingles
    7. Contact Dermatitis
    8. Erythema Migrans
      1. Most Insect Bite reactions are localized (typically <2.5 to 5 cm in size) and resolves in first 48 hours
      2. Erythema Migrans insyead, continues to expand at >48 hours to diameters often >10 cm
    9. Erythema Multiforme
      1. Multiple target lesions each typically <2 cm diameter
    10. Granuloma Annulare
      1. Scaling erythematous lesions with central clearing (esp. hands and feet)
    11. Methicillin Resistant Staphylococcus Aureus (MRSA)
      1. Lesions with necrotic central eschar
    12. Tinea Corporis
    13. Urticaria
  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 times of peak Insect activity (dawn and dusk)
    4. Avoid habitats
      1. Woodpiles
      2. Crawl spaces
      3. Corners of buildings
      4. Standing water
      5. Dense vegetation
    5. 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. Avoid bright colors (wear light colored clothing)
        2. Avoid perfumes
    6. Insect Repellents
      1. See Insect Repellent
      2. DEET (<30% is safe in young children)
        1. Mosquitoes
        2. Fleas
        3. Gnats
        4. Chiggers
      3. Permethrin (Elimite, Nix) on clothes
        1. Ticks
  10. References
    1. Norris (1998) Physician and Sports Med 26(7):47-58
    2. Herness (2022) Am Fam Physician 106(2): 137-47 [PubMed]
    3. Juckett (2013) Am Fam Physician 88(12): 841-7 [PubMed]
    4. Kemp (1998) Postgrad Med 103(6):88-106 [PubMed]

Arachnida (invertebrate) (C0003704)

Definition (CSP) adults nearly always have 4 pairs of segmented legs, and are usually not worm-like.
Definition (MSH) A class of Arthropoda that includes SPIDERS; TICKS; MITES; and SCORPIONS.
Concepts Eukaryote (T204)
MSH D001097
SnomedCT 76222001, 106829009
English Arachnida, Arachnids, Arachnid (organism), Class Arachnida (organism), Class Arachnida, Arachnida (invertebrate), Arachnidas, arachnid, arachnids, Class arachnida, Class arachnida (organism), Arachnid, Class: Arachnida, Arachnid, NOS
Spanish clase Arachnida, clase Arachnida (organismo), arácnido (organismo), arácnido, clase arachnida (concepto no activo), clase arachnida, Arachnida, Arácnidos
French Arachnida, Arachnides
Swedish Arachnida
Czech pavoukovci, Arachnida
Finnish Hämähäkkieläimet
Italian Arachnidi, Arachnida
Japanese クモ目, クモ形綱, しゅ形類, クモ形類, クモ綱, 蛛形類
Portuguese Arácnidos, Arachnida, Aracnídeos
Croatian Not Translated[Arachnida]
Polish Pajęczaki
Norwegian Edderkoppdyr, Arachnida
German Arachnida
Dutch Arachnida, Spinachtigen
Derived from the NIH UMLS (Unified Medical Language System)

Arthropods (C0003903)

Definition (MSH) Members of the phylum Arthropoda, composed of organisms having a hard, jointed exoskeleton and paired jointed legs. It includes the class INSECTS and the subclass ARACHNIDA, many species of which are important medically as parasites or as vectors of organisms capable of causing disease in man.
Definition (NCI) The taxonomic phylum whose members are invertebrates with hard exoskeletons and segmented joints. Organisms in this phylum include the Arachnids, Centipedes, Crustaceans, Insects and the extinct Trilobites.
Definition (CSP) body is semented into 2 or 3 regions, with paired, segmented appendages, and a hardened body wall; periodically sheds and renews the exoskeleton.
Concepts Eukaryote (T204)
MSH D001181
SnomedCT 106762008, 32964001
LNC LP14805-3
English Arthropods, Phylum: Arthropoda, Arthropod, Arthopoda, Phylum Arthopoda, Phylum Arthopoda (organism), Phylum arthropoda - arthropod, Phylum arthropoda - arthropod (organism), arthropoda, arthropod, arthropods, Arthropoda, Arthropod (organism), Arthropoda,82696, Arthropod, NOS
Spanish artrópodo, filo Arthropoda: artrópodo, filo Arthropoda: artrópodo (organismo), filo Arthopoda, Arthopoda, tipo Arthropoda: artrópodo (organismo), filo Arthopoda (organismo), tipo Arthropoda: artrópodo, artrópodo (organismo), tipo: Arthropoda, Arthropoda, Artrópodos
French Arthropodes
Swedish Leddjur
Czech členovci
Finnish Niveljalkaiset
Polish Stawonogi
Norwegian Leddyr, Arthropoda, Artropoder
Portuguese Artrópodos, Arthropoda, Artrópodes
German Arthropoden, Gliederfüßler
Italian Artropodi
Dutch Geleedpotige, Geleedpotigen
Derived from the NIH UMLS (Unified Medical Language System)

Insect Bites (C0021564)

Concepts Injury or Poisoning (T037)
MSH D007299
SnomedCT 271210003, 217707003, 157938009, 269712007, 24734008, 276433004
English Bites, Insect, Bite, Insect, Insect Bite, Insect bite NOS, insect bite (diagnosis), injury caused by animal insect bite, insect bite, nonvenomous insect bite, Bite;insect, insect bites, Insect bite: (& NOS) (disorder), Insect bite: (& NOS), Insect bite NOS (event), Insect bite, Insect bite - wound, Insect bite (morphologic abnormality), Insect bite - wound (disorder), bite; insect, insect; bite, Insect Bites, Insect bite NOS (finding)
Dutch insectenbeet NAO, beet; insect, insect; beet
French Piqûre d'insecte SAI, Morsures d'insectes, Morsures d'insecte
German Insektenstich NNB, Insektenbisse
Italian Morso di insetto NAS, Morsi d'nsetti
Portuguese Mordedura de insecto NE
Spanish Picadura de insecto NEOM, picadura de insecto, SAI (hallazgo), picadura de insecto, SAI (evento), picadura de insecto, SAI, mordedura de insecto, picadura de insecto (anomalía morfológica), picadura de insecto - herida (trastorno), picadura de insecto - herida, picadura de insecto - lesión (trastorno), picadura de insecto - lesión, picadura de insecto
Japanese 昆虫咬傷NOS, コンチュウコウショウNOS
Czech Kousnutí hmyzem NOS
Hungarian Rovarcsípés k.m.n.
Norwegian Insektbitt
Derived from the NIH UMLS (Unified Medical Language System)

Insect Bites and Stings (C0021568)

Definition (MEDLINEPLUS)

Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito, flea, and mite bites usually itch. Insects can also spread diseases. In the United States, some mosquitoes spread West Nile virus. Travelers outside the United States may be at risk for malaria and other infections.

To prevent insect bites and their complications

  • Don't bother insects
  • Use insect repellant
  • Wear protective clothing
  • Be careful when you eat outside because food attracts insects
  • If you know you have severe allergic reactions to insect bites, carry an emergency epinephrine kit
Definition (MSH) Bites and stings inflicted by insects.
Concepts Injury or Poisoning (T037)
MSH D007299
Swedish Insektsbett och insektsstick
English INSECT BITES STINGS, Insect Bites and Stings, Insect Bites and Stings [Disease/Finding], insect bites stings, stings bites insect, bites insect stings, insect stings bites, Bug bites, Insect bite/sting
Czech hmyz - kousnutí a bodnutí
Finnish Hyönteispuremat ja -pistot
Japanese 虫刺咬症, 昆虫刺, 昆虫刺咬傷, 刺虫傷, 刺咬症-昆虫, 昆虫刺症, 虫刺, 虫刺症, 虫さされ, 虫刺され, 昆虫刺傷, 昆虫咬傷
Polish Ukąszenia i ukłucia przez owady
Norwegian Insektbitt og -stikk, Insektstikk og -bitt
Portuguese Mordidas e Picadas de Insetos, Mordeduras e Picadas de Insetos
Dutch Beet/steek insect, Beet en -steek, insekten-, Insektenbeet en -steek, Insektenbeten en -steken, beten en -steken, insekten-
French Morsures et piqûres d'insectes, Morsures et piqûres d'insecte
German Insektenbisse und -Stiche
Italian Morsi e punture di insetti
Spanish Mordeduras y Picaduras de Insectos
Derived from the NIH UMLS (Unified Medical Language System)

Arthropod dermatosis (C0344066)

Concepts Disease or Syndrome (T047)
SnomedCT 240884008
English Arthropod dermatosis, Arthropod dermatosis (disorder)
Spanish dermatosis por artrópodos (trastorno), dermatosis por artrópodos
Derived from the NIH UMLS (Unified Medical Language System)

Arthropod bite (C0853348)

Concepts Injury or Poisoning (T037)
SnomedCT 409981006
Italian Morso di artropode
Japanese 節足動物咬傷, セッソクドウブツコウショウ
Czech Kousnutí členovcem
English arthropod bite, arthropod bites, arthropod; bite, bite; arthropod, Arthropod bite, Arthropod bite (morphologic abnormality)
Hungarian Ízeltlábúharapás
Dutch artropoden; beet, beet; artropoden, geleedpotigenbeet
Portuguese Mordedura de artrópodo
Spanish Mordedura de artrópodo, mordedura de artrópodo (anomalía morfológica), mordedura de artrópodo
French Morsure d'insecte
German Arthropodenbiss
Derived from the NIH UMLS (Unified Medical Language System)

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