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Arthropod Bites and Stings

- Positioning: supine with legs elevated - Oxygen 6 to 8 L/min up to 100%, as needed - IV fluids: Establish 1 to 2 large-bore IV lines. Normal saline rapid bolus 1 to 2 L IV; repeat as needed (pediatrics 20 to 30 mL/kg) - H1 antihistamines: diphenhydramine 25 to 50 mg IV (pediatrics 1 to 2 mg/kg) - β2 agonists: albuterol for bronchospasm nebulized 2.5 to 5 mg in 3 mL - Emergency treatment of refractory cases: consider epinephrine infusion, dopamine, glucagon, vasopressin, large-volume crystalloids (4,5)

- Arthropod bites/stings without anaphylaxis - Tetanus booster, as indicated - Oral antihistamines - Diphenhydramine - Cetirizine - H2 blockers: ranitidine

- Fire ants: characteristically cause sterile pustules. Leave intact: Do not open or drain. - Brown recluse spider: pain control, supportive treatment; surgical consult if d ©bridement needed - Ticks: early removal. Review guidelines for disease prophylaxis and treatment. - Pediculosis: head, pubic, and body lice - First line: permethrin 1% (Nix) topical lotion. Apply to affected area, wash off in 10 minutes. - Alternatives: pyrethrin or malathion 0.5% lotion, ivermectin (not FDA approved for pediculosis) orally - Repeat above treatment in 7 to 10 days. - For eyelash infestation: Apply ophthalmic-grade petroleum jelly BID for 10 days.

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  • The more rapidly anaphylaxis develops, the more likely the reaction is to be severe and potentially life-threatening. Most deaths due to anaphylaxis occur within 30 to 60 minutes of sting.
  • Epinephrine should be given as soon as diagnosis of anaphylaxis is suspected. Delay of epinephrine is associated with fatal anaphylaxis (4,5).
  • Antihistamines and steroids do not replace epinephrine in anaphylaxis, and no direct outcome data regarding their effectiveness in anaphylaxis are available (4,5).
  • Airway management critical if angioedema

GENERAL MEASURES

Local wound care, ice compress, elevation, analgesics

MEDICATION

First Line

  • For arthropod bites/stings with anaphylaxisThere are no randomized controlled trials on treatments, so the following recommendations are all based on expert opinion consensus (5)[C].Epinephrine: most important: IM injection in midanterolateral thigh (vastus lateralis muscle):IM injection: epinephrine 1:1,000 (1 mg/mL): adult: 0.3 to 0.5 mg per dose; pediatric: give 0.01 mg/kg to a maximum dose of 0.5 mg per dose, can repeat every 5 to 15 minutes (5)Positioning: supine with legs elevatedOxygen 6 to 8 L/min up to 100%, as neededIV fluids: Establish 1 to 2 large-bore IV lines. Normal saline rapid bolus 1 to 2 L IV; repeat as needed (pediatrics 20 to 30 mL/kg)H1 antihistamines: diphenhydramine 25 to 50 mg IV (pediatrics 1 to 2 mg/kg)β2 agonists: albuterol for bronchospasm nebulized 2.5 to 5 mg in 3 mLEmergency treatment of refractory cases: consider epinephrine infusion, dopamine, glucagon, vasopressin, large-volume crystalloids (4,5)
  • Arthropod bites/stings without anaphylaxisTetanus booster, as indicatedOral antihistaminesDiphenhydramineCetirizineH2 blockers: ranitidineOral steroids: consider short course for severe pruritus; prednisone or prednisolone 1 to 2 mg/kg once dailyTopical intermediate-potency steroid cream or ointment 3 to 5 daysDesoximetasone 0.05%Triamcinolone 0.1%Fluocinolone 0.025%Wound care: antibiotics only if infectionOther specific therapies:Scorpion stings: Treat excess catecholamine release (nitroprusside, prazosin, β-blockers). Diazepam for muscle spasms. Atropine for hypersalivation (6). Only one FDA-approved scorpion antivenom in United States and should be administered in conjunction with toxicologist. Black widow bites: Treat muscle spasms with diazepam and opioid analgesics PO or IV (6). Antivenom: available but should be administered in conjunction with toxicologist.Poison control should be consulted for questions regarding management of envenomation. Poison Control hotline: 1-800-222-1222.Fire ants: characteristically cause sterile pustules. Leave intact: Do not open or drain.Brown recluse spider: pain control, supportive treatment; surgical consult if d ©bridement neededTicks: early removal. Review guidelines for disease prophylaxis and treatment.Pediculosis: head, pubic, and body liceFirst line: permethrin 1% (Nix) topical lotion. Apply to affected area, wash off in 10 minutes.Alternatives: pyrethrin or malathion 0.5% lotion, ivermectin (not FDA approved for pediculosis) orallyRepeat above treatment in 7 to 10 days.For eyelash infestation: Apply ophthalmic-grade petroleum jelly BID for 10 days.Sarcoptes scabiei scabiesPermethrin 5% cream: Apply to entire body. Wash off after 8 to 14 hours. Repeat in 1 week.Ivermectin: 200 μg/kg PO once; repeat in 2 weeks (not FDA approved for this use)Crotamiton 10% cream or lotion less efficacious; apply daily for 2 days after bathing.

Second Line

Second-line options for anaphylaxis:

  • Ranitidine
  • Methylprednisolone 1 mg/kg for 3 to 4 days or hydrocortisone 200 mg (5)

ISSUES FOR REFERRAL

Refer to allergist with history of anaphylaxis, severe systemic symptoms, or progressively severe reactions

SURGERY/OTHER PROCEDURES

D ©bridement and delayed skin grafting may be needed for brown recluse spider and other bites.

COMPLEMENTARY & ALTERNATIVE MEDICINE

  • Some stings may be treated with a paste of 3 tsp of baking soda and 1 tsp water.
  • None well tested

INPATIENT CONSIDERATIONS

Admission Criteria/Initial Stabilization

Anaphylaxis, vascular instability, neuromuscular events, pain, GI symptoms, renal damage/failure

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

  • Immunotherapy as recommended by allergist/consultant for anaphylaxis or serious reactions; venom immunotherapy cornerstone of treatment for Hymenoptera.
  • Patient-administered epinephrine must be provided to patients with anaphylaxis. Consider "med-alert" identifiers (4,5).

Patient Monitoring

  • Monitor for delayed effects, including infectious diseases from arthropod vectors.
  • Serum sickness reactions, vasculitis (rare)

PATIENT EDUCATION

Avoidance and prevention

PROGNOSIS

  • Excellent for local reactions
  • For systemic reactions, best response with early intervention to prevent cardiorespiratory collapse

COMPLICATIONS

  • Scarring
  • Secondary bacterial infection
  • Arthropod-associated diseases as mentioned earlier
  • Psychological effects, phobias

REFERENCES

11 Tanskersley MS, Ledford DK. Stinging insect allergy: state of the art 2015. J Allergy Clin Immunol Pract. 2015;3(3):315-322.22 Diaz JH. Recognition, management, and prevention of hymenopteran stings and allergic reactions in travelers. J Travel Med. 2009;16(5):357-364.33 Moore SJ, Mordue Luntz AJ, Logan JG. Insect bite prevention. Infect Dis Clin North Am. 2012;26(3):655-673.44 Simons FE, Ardusso LR, Bil ² MB, et al. 2012 update: World Allergy Organization guidelines for the assessment and management of anaphylaxis. Curr Opin Allergy Clin Immunol. 2012;12(4):389-399.55 De Bisschop MB, Bellou A. Anaphylaxis. Curr Opin Crit Care. 2012;18(4):308-317.66 Quan D. North American poisonous bites and stings. Crit Care Clin. 2012;28(4):633-659.

ADDITIONAL READING

  • Centers for Disease Control and Prevention. Protection against mosquitoes, ticks, & other insects & arthropods. http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-2-the-pre-travel-consultation/protection-against-mosquitoes-ticks-and-other-insects-and-arthropods. Accessed 2015.
  • Centers for Disease and Prevention. FAQ. Insect repellent use & safety. http://www.cdc.gov/westnile/faq/repellent.html. Accessed 2015.
  • Centers for Disease Control and Prevention. Tickborne diseases of the United States: a reference manual for health care providers. Third edition, 2015. Handbook available as a PDF at http://www.cdc.gov/ticks/
  • Sicherer SH, Leung DY. Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2012. J Allergy Clin Immunol. 2013;131(1):55-66.
  • Studdiford JS, Conniff KM, Trayes KP, et al. Bedbug infestation. Am Fam Physician. 2012;86(7):653-658.
  • Swanson DL, Vetter RS. Bites of brown recluse spiders and suspected necrotic arachnidism. N Engl J Med. 2005;352(7):700-707.
  • Warrell DA. Venomous bites, stings, and poisoning. Infect Dis Clin North Am. 2012;26(2):207-223.
  • Juckett G. Arthropod bites. Am Fam Physician. 2013; 88(12):841-847.

CODES

ICD10

  • T63.481A Toxic effect of venom of arthropod, accidental, init
  • T63.301A Toxic effect of unsp spider venom, accidental, init
  • T63.484A Toxic effect of venom of oth arthropod, undetermined, init
  • T63.304A Toxic effect of unsp spider venom, undetermined, init encntr

ICD9

  • 919.4 Insect bite, nonvenomous, of other, multiple, and unspecified sites, without mention of infection
  • 989.5 Toxic effect of venom

SNOMED

  • 299971005 insect sting (disorder)
  • 276433004 Insect bite - wound (disorder)
  • 55308005 Poisoning due to insect venom
  • 429305003 Nonvenomous insect bite
  • 15056007 poisoning due to arthropod venom (disorder)

CLINICAL PEARLS

  • Urgent administration of epinephrine is a key to anaphylaxis treatment.
  • Local treatment and symptom management are sufficient in most insect bites and stings.