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Bites and Stings

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Ovid: 5-Minute Sports Medicine Consult, The


Bites and Stings
Steven A. Greer
Basics
Arthropods affect man as pests, by inoculating poison or invading tissue, or by transmitting disease. Inoculation of poison may occur as either a bite or a sting. This discussion is limited to the irritative, poisonous, allergic effects of these pests.
Description
  • Harmful arthropods of the U.S. include (1,2,3):
    • Ants: Fire ants, harvester ants
    • Bees: Bumblebees, sweat bees, honeybees, Africanized (killer) bees
    • Bugs: Kissing, bed, wheel
    • Caterpillars: Puss, browntail, buck, moth saddleback
    • Centipedes
    • Fleas: Human, cat, dog
    • Flies: Deer, horse, black, stable, and biting midges
    • Lice: Body, head, pubic
    • Mites: Itch mite (scabies), red bugs (chiggers)
    • Mosquitoes
    • Scorpions
    • Spiders: Brown recluse, black widow, hobo
    • Ticks: Deer, lone star
    • Wasps: Hornets, wasps
  • Characteristic reactions include:
    • Local tissue irritation, inflammation, and destruction
    • Systemic effects related to inoculated poisons
    • Allergic reactions: Immediate or delayed
  • System(s) affected: Skin/Exocrine
Epidemiology
  • Affects all ages with 0- to 4-yr-olds and 20- to 24-yr-olds at highest risk for nonfatal bites/stings (4)
  • Males = Females
Incidence
  • Common, with ∼1 million nonfatal and 50 fatal cases per year (4,5)
  • Anaphylaxis is estimated at 3% in adults and 0.4–0.8% in children
  • Individual stings from Africanized (killer) bees are no more potent than other bees; the danger lies in their predilection to swarm, causing death by multiple stings.
Prevalence
Ubiquitous, varies by region and season (4)
Risk Factors
  • Living environment (5,6)
  • Climate
  • Season
  • Clothing
  • Lack of protective measures
  • Perfumes, colognes
  • Previous sensitization
  • Young or elderly at more risk for morbidity/mortality
Genetics
No genetic predilection
General Prevention
Prevention/avoidance (5,6,7):
  • Avoid re-exposure in known hypersensitive individuals.
  • Prescribe anaphylactic (ANA kit) or self-administered epinephrine (Epi-Pen), if indicated.
  • Educate on risks of increasing anamnestic responses in the future.
  • Consider desensitization with immunotherapy in severe cases.
  • Cover as much skin as possible.
  • Use repellants on uncovered areas.
  • Apply sunscreen 1st, then repellant.
  • DEET, epicardin, or other proven insect repellants
  • Oil of lemon eucalyptus, PMD, and IR3535 are considered biopesticides by the Environmental Protection Agency (EPA), but be sure to use EPA-approved products, as many versions have not been tested.
  • Permethrin applied to clothes is effective through multiple washings.
  • Permethrin-infused clothing is commercially available and effective.
  • Consider immunization/prophylaxis for travel to endemic areas.
Etiology
  • Local tissue inflammation and destruction from poison (5)
  • Allergic reaction from previous sensitization (0.4–3%)
  • Toxic reaction from large inoculation of poison
Diagnosis
Physical Exam
  • Signs and symptoms (2,3,5,6,8):
    • Erythema
    • Pain
    • Heat
    • Swelling
    • Itching
    • Blisters
    • Secondary infection: Cellulitis, abscess
    • Necrosis
    • Ulceration
    • Drainage
  • Toxic reactions (nonantigenic):
    • Nausea
    • Vomiting
    • Headache
    • Fever
    • Diarrhea
    • Lightheadedness
    • Syncope
    • Drowsiness
    • Muscles spasms
    • Edema
    • Convulsions
  • Systemic reactions (allergic):
    • Itching eyes
    • Facial flushing
    • Generalized urticaria
    • Dry cough
    • Chest/throat constriction
    • Wheezing
    • Dyspnea
    • Cyanosis
    • Abdominal cramps
    • Diarrhea
    • Nausea
    • Vomiting
    • Vertigo
    • Chills/fever
    • Stridor
    • Shock
    • Loss of consciousness
    • Involuntary bowel/bladder action
    • Frothy sputum
    • Respiratory failure
    • Cardiovascular collapse
    • Death
  • Delayed reaction:
    • Serum-sickness-like reactions
    • Fever
    • Malaise
    • Headache
    • Urticaria
    • Lymphadenopathy
    • Polyarthritis
  • Unusual reactions:
    • Encephalopathy
    • Neuritis
    • Vasculitis
    • Nephrosis
    • Extreme fear/anxiety
Diagnostic Tests & Interpretation
Lab
Leukocytosis, thrombocytopenia, hypofibrinogenemia, abnormal coagulation, disseminated intravascular coagulation, proteinuria, hemoglobinemia, hemoglobinuria, myoglobinemia, myoglobinuria, and azotemia are uncommon but possible manifestations in severe reactions.
Pathological Findings
Inflammation, ulceration, vesiculation, pustulation, rupture, eschar, swelling (3,5)
Differential Diagnosis
  • Local reaction: Infection, cellulitis, dermatoses, punctures, foreign bodies
  • Toxic reaction: Chemical exposure/ingestion, medications, IV drug abuse, environmental, plants
  • Allergic reaction: Medications, illicit drugs, foods, topical products, environmental, plants, chemicals
Treatment
  • Long-term treatment (5):
    • Recommended for those with hypersensitivity reaction, but may be considered for individuals with large local reactions
    • Self-administered epinephrine device
    • Hypersensitivity identification
    • Venom immunotherapy for 3–5 yrs is 80–90% effective even after cessation of treatment.
  • Acute treatment (1,2,3,5,8,9):
    • Outpatient or inpatient, depending on individual response to injury
    • Hospitalize for severe systemic reactions with threatened airway obstruction, bronchospasm, hypotension, severe angiodermatitis, or pain

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Medication
First Line
  • Local (depending on severity):
    • Analgesics
    • Antihistamines: Diphenhydramine (Benadryl) 25–50 mg q.i.d.
    • Steroids topical or oral: Prednisone 20–40 mg/day is unproven but may be helpful for large local reactions.
    • Antibiotics only if there is a secondary infection
  • Systemic (depending on severity and reaction type):
    • Epinephrine [1:1,000] SC: To combat urticaria, wheezing, angioedema—child 0.01 mL/kg, adult 0.3–0.5 mL
    • Diphenhydramine: 25–50 mg IV or IM to combat urticaria, wheezing, angioedema
    • Albuterol 5 mg inh and ipratropium bromide 0.5 mg inh: Bronchospasm
    • IV fluids (Ringer's lactate): If needed for hypotension, hypovolemia
    • Dopamine: 200 mg in 250 mL at 5 mcg/kg/min to correct vascular collapse
  • Titrate to maintain systemic BP over 90 mm Hg:
    • Hydrocortisone: 100–250 mg IV, if needed, for severe urticaria or spider bite
    • Tetanus prophylaxis and antibiotics: Only if secondary infection, rarely indicated
    • Diazepam (Valium): 5–10 mg, if needed, for severe muscle spasms
    • Morphine or meperidine (Demerol): If needed for pain
  • Antivenins may be appropriate based on availability, identification of organism, and previous sensitivity.
  • Topical insecticides:
    • Lice: 1% permethrin (Nix, Elimite) is still considered first line despite up to 50% resistance. 0.5% Malathion (Ovide) may be used as initial choice or for permethrin failure. 1% lindane (Kwell) or pyrethrin (Rid) is also effective.
    • Scabies: 5% permethrin is drug of choice, but 10% crotamiton (Eurax) and lindane are effective.
  • Contraindications: Refer to manufacturer's literature.
  • Precautions:
    • Dosing appropriate to age
    • If severe reaction, don't delay treatment.
    • Severe vascular collapse may require central pressure monitor.
  • Significant possible interactions: Refer to manufacturer's literature.
Second Line
  • Alternative drugs (9):
    • Other H1 antihistamines (eg, loratadine [Claritin], fexofenadine [Allegra], etc.)
    • H2 blockers (eg, ranitidine [Zantac], cimetidine [Tagamet], famotidine [Pepcid], etc.)
    • Oral ivermectin (Mectizan) appears effective for lice and scabies, but is not FDA-approved for this purpose.
Additional Treatment
General Measures
  • First aid measures, local treatment, activate emergency services in severe reactions. If history of allergy or large envenomations, don't wait to seek emergency care (2,3,5,6).
  • Use ANA kit and over-the-counter antihistamines, if available and required.
  • Local (depending on severity):
    • Remove stinger (scrape it out—don't squeeze with tweezer).
    • Cleanse wound.
    • Ice packs to bite or sting site (alternate 10 min on/10 min off)
    • Elevation of affected part
    • Debride ulcers.
    • Drain abscesses.
  • Systemic (depending on severity and type of reaction): Home use—Epi-Pen:
    • Adequate airway (intubation, tracheostomy): If needed to bypass obstruction
    • Oxygen (4–6 L/min): If needed for respiratory distress
    • Hospitalize and observe 24–48 hrs.
Complementary and Alternative Medicine
  • Oil of lemon eucalyptus, PMD, and IR3535 are considered biopesticides by the EPA, but be sure to use EPA-approved products, as essential oils have not been tested (6,11).
  • Tumeric may help inflammation. Animal studies show promise, but no proof in humans and no dose data.
Surgery/Other Procedures
Optimal treatment of necrotic spider bites is not well defined. Surgical repair may be required for severe ulcerative lesions, but not until primary necrotizing process is complete (2,3,6).
Ongoing Care
Follow-Up Recommendations
No activity restrictions
Patient Monitoring
Follow-up wound care
Diet
No special diet; nothing by mouth if severe systemic reaction
Patient Education
  • Protective measures, ANA kit/Epi-Pen use, risks (5,6)
  • Individuals with known sensitivity should wear medical identification (bracelet, tag) or carry a card.
Prognosis
Expected course (2,5):
  • Minor reactions—excellent
  • Severe reactions—excellent with early, appropriate treatment
Complications
  • Infection (2,5,9):
    • Bacterial
    • Arthropod-associated diseases with tick, fly, bug, and mosquito bites (eg, lyme borreliosis, rickettsial disease [Rocky Mountain spotted fever], arboviral encephalitis, malaria, leishmaniasis, trypanosomiasis, dengue)
  • Scarring
  • Drug reactions
  • Multisystem failure
  • Death
References
1. Isselbacher KJ, et al., eds. Harrison's principles of internal medicine. 13th ed. New York, McGraw-Hill, 1994.
2. Tintinalli JE, Krome RL, eds. Emergency medicine. New York, McGraw-Hill, 1988.
3. MMWR: Necrotic arachnidism-Pacific Northwest, 1996;45(21).
4. Center for Disease Control and Prevention National Center for Injury Prevention and Control http://www.cdc.gov/injury/wisqars/index.html
5. Moffitt JE, Golden DBK, Reisman RE, et al. Stinging insect hypersensitivity: a practice parameter update. J Allergy Clin Immunol. 2004;114:869–886.
6. Burnette GW, et al., eds. CDC health information for international travel 2010, Mosby, 2009.
7. Mosquitoes and mosquito repellants: a clinician's guide. Ann Int Med. 1198;128(ll):931–940.
8. Schroeder SA, Krupp MA, Tieme LM, et al. eds. Current medical diagnosis and treatment. Norwalk, CT: Appleton & Lange, 1989.
9. Pickering L, ed. 2009 red book: report of the committee on infectious diseases, 28th ed. American Academy of Pediatrics, 2009.
10. The Medical Letter. Vol 40 (issue 1017) Jan 2, 1998.
11. Jurenka JS: Anti-inflammatory properties of curcumin, a major constituent of Curcuma longa: a review of preclinical and clinical research. Altern Med Rev. 2009;14(2):141–153.
Pediatric Considerations
Not a contraindication to appropriate management
Codes
ICD9
  • 919.5 Insect bite, nonvenomous, of other, multiple, and unspecified sites, infected
  • 989.5 Toxic effect of venom


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