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Bites, Insects: Treatment & Medication
Updated: Oct 13, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Prehospital Care
- If the bee stinger is present in the wound, it should be removed. Although conventional teaching suggested scraping the stinger out to avoid squeezing remaining venom from the retained venom gland into the victim, involuntary muscle contraction of the gland continues after evisceration and the venom contents are quickly exhausted. Immediate removal is the important principle and the method of removal is irrelevant.
- Most insect bites may be treated acutely with a compress after routine wound cleaning with soap and water to minimize the possibility of infection.
- For a large local reaction, ice packs may minimize swelling. Apply ice for no more than 15 minutes at a time using a cloth barrier between ice and skin to prevent direct thermal injury to the skin.
- Epinephrine is the mainstay of prehospital treatment of a systemic reaction; the route of administration (subcutaneous, intramuscular, intravenous [IV], endotracheal) depends on the patient's condition and the expertise of the prehospital provider. Systemic antihistamines and corticosteroids, if available, help manage systemic reactions. Many patients who are allergic to stings carry commercially available bee sting kits containing an autoinjector of epinephrine. Refer to Hymenoptera Stings.
- Topical antihistamines should not be applied over large surface areas, and they should not be used concurrently with systemic H1 antihistamines. Systemic anticholinergic toxicity may result from misuse of these medications.
- Use of H2-blocking drugs (usually used to reduce gastric acid secretion) may be used concurrently with H1-blocking antihistamines.
- In many patients, transport to a hospital is not necessary. Those requiring transport include patients who develop signs or symptoms of a systemic response or individuals with a history of insect-related anaphylaxis. A phone call to the regional poison center may save a costly visit to the ED.
Emergency Department Care
- Endotracheal intubation and ventilatory support may be required for severe anaphylaxis or angioedema involving the airway.
- Treat emergent anaphylaxis in an atopic individual with an initial intramuscular injection of 0.3-0.5 mL of 1:1000 epinephrine. This may be repeated every 10 minutes as needed.
- A bolus of IV epinephrine (1:10,000) may be used cautiously in severe cases.
- Solution of 1:10,000 typically is found in 10-mL vials. Repeated 1-mL doses are a reasonable initial approach in a critically ill patient with anaphylaxis.
- Once a positive response is achieved, these boluses can be followed by a carefully monitored, continuous epinephrine infusion.
- Use extra care in monitoring formulation, concentration, and dose when administering IV epinephrine to avoid inadvertent overdose.
- Severely hypotensive patients may require a large volume of IV fluids. Monitor for angioedema and pulmonary edema.
- Antihistamines, both H1 and H2 blockers, are useful in treating systemic reactions. Corticosteroids also are indicated routinely in such patients.
- Refer to Anaphylaxis and Serum Sickness for further guidance.
- Ensure appropriate tetanus prophylaxis.
- Undefined erythema and swelling seen may be difficult to distinguish from cellulitis. As a general rule, infection is present in a minority of cases and antibiotic prophylaxis is not recommended.
- Related diagnostic and treatment guidelines are available on anaphylaxis, travel medicine, and referral guidelines (also see Further Reading).9,10,11
Consultations
- In cases in which determining the insect species is important, a health department, agriculture extension, or university entomologist may be useful.
- In cases of potential vector-borne disease transmission, an infectious disease specialist may be of help.
- If the potential infection is associated with travel to a tropical region, consider contacting a tropical medicine specialist or the Centers for Disease Control and Prevention (CDC) at 1-877-394-8747 (Traveler's Health Hotline).
- A regional poison center may be of assistance in difficult or complicated cases or for general information.
Medication
Goals of therapy are to treat anaphylaxis and prevent complications.
Cardiovascular agents
Act to decrease the muscle tone in the small and large pulmonary airways and increase vascular tone.
Epinephrine (Adrenalin, Bronitin, EpiPen)
Drug of choice for shock, angioedema, airway obstruction, bronchospasm, and urticaria in severe anaphylactic reactions. Administer IM; administer IV to patients in extremis; may be administered SL or ET when no IV access available. Continuous infusion may be given in cases of refractory shock.
Adult
1 mL 1:10,000 solution slow IV; repeat prn
0.1-1 mcg/kg/min IV infusion
0.3-0.5 mL 1:1000 solution IM/SL/SQ q10-15min
1 mL 1:1000 solution in 10 mL NS ET
Pediatric
0.01 mL/kg (min 0.1 mL) 1:10,000 solution IV prn
0.1-1 mcg/kg/min IV infusion
0.01 mL/kg (min 0.1 mL) 1:1000 solution IM/SL/SQ q15min
0.01 mL/kg (min 0.1 mL) 1:1000 solution in 1-3 mL NS ET
Epinephrine coadministered with other sympathomimetics may have additive effects; beta-blockers antagonize therapeutic effects of epinephrine; digitalis may potentiate proarrhythmic effects of epinephrine; TCAs and MAOIs potentiate cardiovascular effects of epinephrine; phenothiazines may decrease BP when coadministered with epinephrine
In a life-threatening anaphylactic reaction, epinephrine may be given with appropriate caution when any of the following relative contraindications are present: coronary artery disease; uncontrolled hypertension; serious ventricular dysrhythmias; second stage of labor
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in elderly patients and those with prostatic hypertrophy, hypertension, cardiovascular disease, diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency; rapid IV infusions may cause death from cerebrovascular hemorrhage or cardiac dysrhythmias
Bronchodilators
Through activation of cyclic AMP, beta agonists stimulate the ATPase pump, thereby shifting potassium into the intracellular compartment and stimulating an adrenergic response.
Albuterol (Ventolin)
Beta agonist useful in treating bronchospasms refractory to epinephrine. Relaxes bronchial smooth muscle by action on beta2 receptors and has little effect on cardiac muscle contractility. Numerous inhaled beta agonists are used for treatment of bronchospasm; albuterol is used most commonly.
Adult
0.5 mL 0.5% solution in 2.5 mL NS nebulized q15min
Pediatric
0.03-0.05 mL/kg 0.5% solution in 2.5 mL NS via nebulizer q15min
Increases toxicity of beta-blocking and alpha-blocking agents and halogenated inhalational anesthetics
May be given in a life-threatening anaphylactic reaction, even when the following relative contraindications are present: severe coronary insufficiency; uncontrolled severe hypertension
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in elderly patients and those with prostatic hypertrophy, hypertension, cardiovascular disease, diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency; rapid IV infusions may cause death from cerebrovascular hemorrhage or cardiac dysrhythmias
Antihistamines
Prevent histamine response in sensory nerve endings and blood vessels; more effective in preventing histamine response than in reversing it. H2 antihistamines are useful in treatment of anaphylactic reactions when used concomitantly with H1 antagonists. Many H2 blockers are available. Cimetidine is the prototype drug.
Diphenhydramine (Benadryl)
Used for symptomatic relief of allergic symptoms caused by histamines released in response to allergens; many effective H1 blockers; diphenhydramine is effective and widely available.
Adult
50 mg PO q4-6h
25-50 mg IV/IM q4-6h
Pediatric
5 mg/kg/d PO divided q6h-8h
Severe cases: 1-2 mg/kg IV q6h; alternatively, 1-2 mg/kg IM q6h
Potentiates effect of CNS depressants; due to alcohol content, do not give syr dosage form to patient taking medications that can cause disulfiramlike reactions
Documented hypersensitivity; MAOIs
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction
Cimetidine (Tagamet)
An H2 antagonist that, when combined with H1 type, may be useful to treat itching and flushing in anaphylaxis, pruritus, urticaria, and contact dermatitis that do not respond to H1 antagonists alone. Use in addition to H1 antihistamines.
Adult
300 mg PO/IV/IM q6h
Pediatric
5-10 mg/kg PO/IV/IM q6h
Can increase blood levels of theophylline, warfarin, TCAs, triamterene, phenytoin, quinidine, propranolol, metronidazole, procainamide, and lidocaine
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Elderly patients may experience confusional states; may cause impotence and gynecomastia in young males; may increase levels of many drugs; adjust dose or discontinue treatment if changes in renal function occur
Corticosteroid, Systemic
Have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli. Prednisone and methylprednisolone are typical drugs of this class. Oral bioavailability is generally similar to parenteral; administer oral prednisone when indicated if a patient is not in extremis and can comfortably take PO; administer parenteral steroid when indicated for a patient in more severe circumstances.
Prednisone
Believed to ameliorate delayed effects of anaphylactic reactions and may limit biphasic anaphylaxis. Doses below are general guidelines for usage; dosing is highly individualized.
Adult
40-60 mg/d PO qd or divided bid/qid; no taper required if used for 5-7 d.
Pediatric
1-2 mg/kg PO qd or divided bid/qid; no taper required if used for 5-7 d.
Coadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Documented hypersensitivity; viral infection, peptic ulcer disease, hepatic dysfunction, connective tissue infections, and fungal or tubercular skin infections; GI bleeding or ulceration
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use
Methylprednisolone (Solu-Medrol, Depo-Medrol)
Useful to treat inflammatory and allergic reactions. By reversing increased capillary permeability and suppressing PMN activity, may decrease inflammation.
A multitude of corticosteroid preparations is available. Methylprednisolone is widely available in the ED due to other uses (ie, acute asthma, spinal cord injury) and is supplied in both parenteral and oral formulations.
Adult
2-60 mg PO qd
40-250 mg IV/IM q6h
Pediatric
1-2 mg/kg PO/IV/IM qd
NSAIDs may cause ulcers when taken concurrently; anticholinesterases may increase weakness in patients with myasthenia gravis when taken concurrently with steroids; risk exists of possible viral dissemination with live virus vaccines
Documented hypersensitivity; some evidence exists for fetal harm from corticosteroids (consider both benefits and risks of use during pregnancy); consider risks (eg, dissemination, activation, certain infections) when prescribing for immunosuppressed patients
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Short-term use of corticosteroids, even in large doses, has minimal harmful effects; long-term usage has multiple adverse effects; possible complications include hyperglycemia, edema, osteonecrosis, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, growth suppression, myopathy, or infections
Toxoids
For active immunity against tetanus.
Tetanus toxoid
Used to induce active immunity against tetanus in selected patients. The immunizing agents of choice for most adults and children > 7 y are tetanus and diphtheria toxoids. Necessary to administer booster doses to maintain tetanus immunity throughout life.
Pregnant patients should receive only tetanus toxoid, not a diphtheria antigen-containing product.
In children and adults, may administer into deltoid or midlateral thigh muscles. In infants, preferred site of administration is mid thigh laterally.
Adult
Primary immunization: 0.5 mL IM; give 2 injections 4-8 wk apart and a third dose 6-12 mo after second injection
Booster dose: 0.5 mL q10y
Pediatric
Administer as in adults
Patients receiving immunosuppressants, including corticosteroids or radiation therapy, may remain susceptible despite immunization due to poor immune response; cimetidine may enhance or augment delayed-hypersensitivity responses to skin-test antigens; avoid concurrent use of medication with systemic chloramphenicol since it may impair amnestic response to tetanus toxoid; concurrent use of tetanus immune globulin may delay development of active immunity by several days (interaction is nevertheless clinically insignificant and does not preclude concurrent use)
Documented hypersensitivity; history of any type of neurologic symptoms or signs following administration of this product; FDA recommends that elective tetanus immunization be deferred during any outbreak of poliomyelitis because tetanus toxoid injections are an important cause of provocative poliomyelitis
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Do not use to treat actual tetanus infections or for immediate prophylaxis of unimmunized individuals (use instead tetanus antitoxin, preferably human tetanus immune globulin); diminished antibody response to active immunization may be seen in patients receiving immunosuppressive therapy; better to defer primary diphtheria immunization until immunosuppressive therapy discontinued; routine immunization of symptomatic and asymptomatic HIV-infected persons is recommended
Immunoglobulins
Consists of administration of immunoglobulins pooled from serum of immunized patients.
Tetanus immune globulin (Hyper-Tet)
Used for passive immunization of any person with a wound that may be contaminated with tetanus spores.
Adult
Prophylaxis: 250-500 U IM in opposite extremity to tetanus toxoid lesion
Clinical tetanus: 3,000-10,000 U IM
Pediatric
For prophylaxis: 250 U IM in opposite extremity to tetanus toxoid
Clinical tetanus: 3,000-10,000 U IM
None reported
Since antibodies in globulin preparation may interfere with immune response to vaccination, do not administer within 3 mo of live virus immune globulin administration; may be necessary to revaccinate persons who received immune globulin shortly after live virus vaccination
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Persons with isolated IgA deficiency have potential for developing antibodies to IgA and may have anaphylactic reactions to subsequent administration of blood products that contain IgA; do not perform skin testing since intradermal injection of concentrated gamma globulin may cause localized area of inflammation and can be misinterpreted, causing medication to be withheld from a patient not allergic to this material; true allergic responses to human gamma globulin given in prescribed IM manner are extremely rare; do not admix with other medications since usually incompatible
More on Bites, Insects |
| Overview: Bites, Insects |
| Differential Diagnoses & Workup: Bites, Insects |
 Treatment & Medication: Bites, Insects |
| Follow-up: Bites, Insects |
| Multimedia: Bites, Insects |
| References |
| Further Reading |
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Further Reading
Clinical guidelines
The diagnosis and management of anaphylaxis: an updated practice parameter.
American Academy of Allergy, Asthma and Immunology - Medical Specialty Society
American College of Allergy, Asthma and Immunology - Medical Specialty Society
Joint Council of Allergy, Asthma and Immunology - Medical Specialty Society. 1998 Jun (revised 2005 Mar). 41 pages. NGC:004211
Consultation and referral guidelines citing the evidence: how the allergist-immunologist can help.
American Academy of Allergy, Asthma and Immunology - Medical Specialty Society. 2006 Feb. 29 pages. NGC:005003
The practice of travel medicine: guidelines by the Infectious Diseases Society of America. Infectious Diseases Society of America - Medical Specialty Society. 2006. 96 pages. NGC:005086
Clinical trials
Cause of Unexplained Anaphylaxis
Population Pharmacokinetics of Benznidazole in Children With Chagas Disease
Immunogenicity, Safety and Interchangeability of Two Tbe Vaccines Administered According to a Conventional Schedule in Children
Keywords
insect bite, bug bites, Insecta, Hymenoptera, Arachnida, anaphylactic shock, Lyme disease, Chagas disease, trypanosomiasis, tick-borne encephalitides, blackflies, Simuliidae, onchocerciasis, river blindness, dermatitis, cellulitis, urticaria, myiasis, fly larvae, human botflies, NewWorld screwworms, Old World screwworms, Wohlfahrtia flies, Tumbu flies, fly maggots, delusional parasitosis, plant-eating phytophagous insects, cockroach bite, earwigs, reduviid bug, horsefly bites, mosquito, malaria, angioedema
