eMedicine Specialties > Emergency Medicine > Environmental

Fire Ant Bites: Treatment & Medication

Author: James P Ralston, MD, President, Dermatology Center of McKinney
Coauthor(s): Ronald P Rapini, MD, Josey Professor and Chair, Department of Dermatology, Professor of Pathology, University of Texas Medical School at Houston and MD Anderson Cancer Center
Contributor Information and Disclosures

Updated: Nov 10, 2009

Treatment

Medical Care

  • Local stings: Cool compresses and oral antihistamines are recommended for mild reactions. Corticosteroids can be used topically or intralesionally for anti-inflammatory effect.
  • Multiple stings: Systemic corticosteroid use is controversial in patients with extensive lesions who do not have systemic allergic reactions or generalized skin reactions.
    • Large doses of corticosteroids and intravenous fluids may complicate the treatment of patients with preexisting cardiovascular disease.
    • The immunosuppressive effect of corticosteroids may predispose patients to secondary infection.
    • Oral antihistamines and topical corticosteroids are recommended in most cases; nevertheless, some practitioners still use prednisone or other systemic steroids to treat patients with numerous lesions.
  • Anaphylaxis: Acute management of fire ant anaphylaxis is identical to treatment of anaphylaxis from other causes. Subcutaneous epinephrine is used and repeated every 10-15 minutes as needed to reverse the symptoms.

Consultations

An allergist/immunologist consultation for evaluation and possible skin or in vitro testing for fire ant hypersensitivity is appropriate for any patient who has a systemic reaction to a fire ant sting. Consultation should be considered if the patient meets 1 of the following criteria:

  • Experiences anaphylaxis with a fire ant sting as a possible cause
  • Needs education regarding fire ant avoidance or emergency treatment
  • May need venom immunotherapy
  • Has a coexisting condition that may complicate treatment of anaphylaxis (eg, using beta-blockers, having hypertension or cardiac arrhythmias)

Diet

No dietary changes are recommended; however, patients should have nothing by mouth if experiencing a severe systemic reaction.

Activity

No restriction in activity is required; however, rest is recommended in severe cases to possibly slow the spread of the reaction.

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Antihistamines

These agents are for mild-to-severe reactions.


Diphenhydramine (Benadryl, Benylin)

For symptomatic relief of symptoms caused by release of histamine in allergic reactions.

Adult

25-50 mg PO qid for local reactions
25-50 mg IV/IM for urticaria, wheezing, and angioedema

Pediatric

<2 years: Not established
2-6 years: 6.25-12.5 mg PO q4-6h
6-12 years: 12.5-25 mg PO q4-6h
>12 years: 25-50 mg PO q4-6h

Potentiates effect of CNS depressants; because of alcohol content, do not give syr dosage form to patient taking medications that can cause disulfiramlike reactions; concomitant alkaloids present in belladonna, antidepressants with strong anticholinergic effects (eg, amitriptyline, trimipramine, amoxapine, doxepin, imipramine, nortriptyline, maprotiline), or phenothiazines with strong anticholinergic effects (eg, chlorpromazine, triflupromazine, thioridazine) and antihistamines may increase possibility of adynamic ileus, urinary retention, or chronic glaucoma (more prominent in elderly patients)

Documented hypersensitivity; acute asthma; newborns; breastfeeding

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction; elderly more susceptible to side effects; caution in history of bronchial asthma, cardiovascular disease or hypertension; may cause excitation in young children

Nonsteroidal anti-inflammatory drugs

These agents relieve pain and reduce inflammation.


Ibuprofen (Ibuprin, Advil, Motrin)

Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Adult

400 mg PO q4-6h prn

Pediatric

4-10 mg/kg PO q6-8h prn

Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Documented hypersensitivity; peptic ulcer disease; recent GI tract bleeding or perforation; high risk of bleeding; renal insufficiency

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Class D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy

Corticosteroids

These agents have anti-inflammatory properties and cause profound and varied metabolic effects. Corticosteroids modify the body's immune response to diverse stimuli. A short course may be used for severe local reactions.


Prednisone (Deltasone, Orasone, Sterapred)

May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity. Many dosing regimens have been used.

Adult

20 mg PO qd for 5 d

Pediatric

Not established

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, fungal, tubercular skin, or connective tissue infections; peptic ulcer disease; hepatic dysfunction; GI tract disease

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

Anaphylaxis treatment kit

This agent is used for anaphylaxis reactions.


Epinephrine (EpiPen, Adrenalin)

DOC for treating anaphylactoid reactions. Has alpha-agonist effects that include increased peripheral vascular resistance, reversed peripheral vasodilatation, systemic hypotension, and vascular permeability. Beta-agonist effects of epinephrine include bronchodilatation, chronotropic cardiac activity, and positive inotropic effects.

Adult

0.1-0.5 mg IM/SC q10-15min (1:1000 solution)
Autoinjector: 0.3 mg IM (0.3 mL of 1:1000 sol); may repeat if severe anaphylaxis persists
Injectable sol: 0.2 to 1 mg SC

Pediatric

Neonates: 0.01-0.03 mg/kg IV/ET q3-5min prn
Infants/children: 0.01 mg/kg IM once; alternatively, 0.15 to 0.3 mg IM depending on body weight; 0.01 mg/kg may be appropriate for patients weighing <30 kg

Alpha-blockers antagonize vasoconstriction; antihistamines may potentiate adverse cardiac effects; beta-blockers antagonize effects; cyclopropane may increase risk of arrhythmias; digoxin may increase risk of arrhythmias; ergot alkaloids increase risk of severe hypertension; halothane may increase risk of arrhythmias; TCAs may potentiate adverse cardiac effects; thyroid hormones may potentiate adverse cardiac effects; concurrent administration with chlorpromazine may result in decrease in blood pressure with reflex tachycardia
Chlorpromazine may reduce effect by approximately 50%; coadministration with MAOI including linezolid may cause clinically significant hypertensive effects; concurrent use of guanethidine and direct-acting sympathomimetic amines (eg, epinephrine, methoxamine, norepinephrine, phenylephrine) can result in severe hypertension

Documented hypersensitivity; cardiac arrhythmias or angle-closure glaucoma; local anesthesia in areas such as fingers or toes because vasoconstriction may produce sloughing of tissue; during labor (may delay second stage of labor); cardiac dilatation and coronary insufficiency (injection); concurrent use with cyclopropane or halogenated hydrocarbon anesthetic

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

Caution in elderly persons, prostatic hypertrophy, hypertension, cardiovascular disease, diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency; rapid IV infusions may cause death from cerebrovascular hemorrhage or cardiac arrhythmias

More on Fire Ant Bites

Overview: Fire Ant Bites
Differential Diagnoses & Workup: Fire Ant Bites
Treatment & Medication: Fire Ant Bites
Follow-up: Fire Ant Bites
Multimedia: Fire Ant Bites
References
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References

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  3. Williams DF, deShazo RD. Biological control of fire ants: an update on new techniques. Ann Allergy Asthma Immunol. Jul 2004;93(1):15-22. [Medline].

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Further Reading

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Keywords

fire ant bites, imported fire ants, fire ant bite treatment, fire ant bite symptoms, Solenopsis invicta, S invicta, , , , , , , , , Hymenoptera, hypersensitivity reactions, Soli 1-4, anaphylaxis, anaphylactic reaction, fire ant-induced anaphylaxis

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Contributor Information and Disclosures

Author

James P Ralston, MD, President, Dermatology Center of McKinney
James P Ralston, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, and Texas Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Ronald P Rapini, MD, Josey Professor and Chair, Department of Dermatology, Professor of Pathology, University of Texas Medical School at Houston and MD Anderson Cancer Center
Ronald P Rapini, MD is a member of the following medical societies: American Academy of Dermatology, American Dermatological Association, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Society for Investigative Dermatology, Southern Medical Association, and Texas Medical Association
Disclosure: Elsevier publishers Royalty Independent contractor

Medical Editor

Daniel J Hogan, MD, Clinical Professor of Internal Medicine (Dermatology), NOVA Southeastern University; Investigator, Hill Top Research, Florida Research Center
Daniel J Hogan, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Contact Dermatitis Society, and Canadian Dermatology Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center
Michael J Wells, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Jeffrey J Miller, MD, Associate Professor of Dermatology, Penn State University College of Medicine; Staff Dermatologist, Penn State Milton S Hershey Medical Center
Jeffrey J Miller, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Professors of Dermatology, North American Hair Research Society, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

CME Editor

Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania
Joel M Gelfand, MD, MSCE is a member of the following medical societies: Society for Investigative Dermatology
Disclosure: AMGEN Consulting fee Consulting; AMGEN Grant/research funds None; Genentech Consulting fee Consulting; Centocor Consulting fee Consulting; Centocor Grant/research funds None; Covance Consulting fee Consulting; Shire  Consulting

Chief Editor

Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

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