Biting and stinging insects may cause allergic reactions. Stinging insects include aphids (honeybees, bumblebees), vespids (yellow jackets, hornets, wasps), and formicids (fire and harvester ants). Biting insects include Triatoma (kissing bugs, conenose bugs), Culicidae (mosquitoes), Tabanidae (horseflies, deerflies), spiders (black widow, brown recluse), and others (bedbugs, black flies). There are more allergic reactions to stinging insects (0.4% to 4% of the United States population) than to biting insects. Approximately 40 stings each year are fatal.

• Increased risk of systemic reaction if previous sting resulted in urticaria or airway obstruction
• Males—2:1 predominance
• Age—elderly (death more common) and children (for frequency of stings but not for fatal reactions)

Stinging insects:

• Large local reactions—pinprick sensation, red papule or wheal, site of bite is warm and tender, edema, possible ulceration or necrosis
• Systemic toxic reactions—shortness of breath, vomiting, diarrhea, fever, muscle spasms, dizziness, loss of consciousness
• Systemic reactions (anaphylaxis)—generalized urticaria, pruritus, erythema, angioedema (e.g., of lips or periorbital area), laryngoedema, asthma, abdominal cramps, diarrhea, hypotension secondary to anaphylactic shock, possible respiratory or cardiovascular failure

Biting insects:

• Urticarial or pruritic papules, pruritic wheals
• Arthus reaction and systemic symptoms; anaphylactic reactions (rare)
• Lesions, crusting, and infection from excoriation
• Myiasis (cutaneous, intestinal, or atrial larvae infestation)
• Systemic infections: Lyme disease, Rocky Mountain Spotted fever, plague, malaria, dengue fever, etc.

• Lyme disease
• Coronary and respiratory diseases
• Anaphylaxis from another source (e.g., insulin, latex, etc.)

Check patient for papules or wheals that spread. Evaluate presence of a systemic reaction (e.g., difficulty breathing, nausea, diarrhea, fever, muscle spasms). Evaluate lesions for infection from scratching. Assess patients who have traveled to Central or South America or Africa for myiasis.

• CBC. Sedimentation rate. Lyme titer.
• Skin tests (using Hymenoptera venoms) determine venom-specific immunoglobulin E (IgE) antibodies.
• Radioallergosorbent test (RAST) determines clinical sensitivity.
• Immunoglobulin G (IgG) levels—low venom-specific levels are associated with treatment failure in yellow jacket and mixed vespid immunotherapy.

Toxic reactions:

• Nonimmunologic
• Cutaneous reactions mediated by IgE or IgG antibodies
• Leukocyte histamine release

Systemic reactions:

• Endogenous vasoactive materials released as a result of allergen–IgE interaction with mast cell and basophil surfaces
• Elevated IgE in 80% of patients with positive skin tests

• Systemic reactions only—pure venom skin test determines sensitivity but cannot discriminate local from systemic reactions.

Local reactions usually do not require treatment unless they are severe. Anaphylaxis is a medical emergency. For large local reactions (most resolve in three to seven days with no treatment):

• Remove stinger and cleanse wound.
• Apply ice pack or cool compresses.
• Apply paste of 1 tsp. meat tenderizer mixed with 1 tsp. water to stinger site.

For systemic reactions:

• Recline, elevating lower extremities.
• Venous tourniquet decreases systemic absorption.
• Maintain airway and give oxygen.

• Antihistamines and analgesics can be taken for pruritus and swelling.
• Topical steroids and systemic glucocorticoids are commonly used but with poor scientific evidence.
• Antibiotics if infection is suspected.

For systemic reactions:

• Aqueous epinephrine (1:1,000, 0.3 to 0.5 ml; 0.01 ml per kg for children)—repeat dosage every 15 to 20 minutes as necessary.
• Intravenous epinephrine (1:100,000) can be administered in an acute care facility for anaphylactic shock.
• Nebulized epinephrine can help alleviate upper-airway edema.
• Parenteral antihistamines (e.g., diphenhydramine hydrochloride [Benadryl], 5 mg per kg each 24 hours in divided doses) increase systemic vascular resistance, elevate diastolic pressure, decrease itching; higher doses for patients not responding to epinephrine.

High doses of flavonoids and vitamins may reduce severity and duration of reactions from insect bites as well as reducing recurrent reactions. Homeopathic remedies can provide relief.

• B complex (50 to 100 mg/day), especially B1 (50 to 100 mg one to two times/day) and B12 (1,000 mcg/day) can be used in prevention as a mosquito repellant.
• Vitamin C helps to stabilize mast cells and reduce histamine release. For severe reactions take 1,000 mg every two hours to bowel tolerance (i.e., loose stools) which may be over 10,000 mg/day. After acute episode, take 1,000 mg tid to qid.
• Bromelain (250 to 500 mg qid between meals) is a proteolytic enzyme that has anti-inflammatory effects (also found in commercial meat tenderizer preparations). Combined with saliva and applied to the sting or bite they help to break down the proteins in the venom.

Herbs are generally a safe way to strengthen and tone the body's systems. Ascertain a diagnosis before pursuing treatment. Herbs may be used as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, teas should be made with 1 tsp. herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Drink 2 to 4 cups/day. Tinctures may be used singly or in combination as noted.

• Licorice root (Glycyrrhiza glabra) supports the immune system and reduces inflammation. Take 500 to 1,000 mg every three to four hours during acute reaction; contraindicated in hypertension.
• Quercetin is a flavonoid that has powerful anti-inflammatory effects. Take 500 to 800 mg bid for severe reactions. For mild to moderate reactions, take 500 mg qid. People with extreme sensitivities to onions may not tolerate quercetin.
• Turmeric (Curcuma longa) is an anti-inflammatory that potentiates the effects of bromelain. Take 250 to 500 mg qid with bromelain.
• Herbs that increase immune function, enhance peripheral and lymphatic circulation, and help to restore dermal integrity may be helpful in reducing the severity and duration of the allergic response. Combine equal parts of coneflower (Echinacea purpurea), cleavers (Galium aparine), oatstraw (Avena sativa), red clover (Trifolium pratense), elder (Sambucus nigra), and marigold (Calendula officinalis). This is best used as a tea, 4 to 6 cups/day, to increase hydration. Tincture may be used as well (30 to 60 drops qid).
• Poultice of raw grated potato or plantain leaves (Plantago lanceolata) may soothe itching, relieve swelling, and enhance healing.
• Make a strong tea from peppermint (Mentha piperita) using 1 heaping tsp./cup. Place in spray bottle and chill. Spray on stings and bites to relieve itching.
• Witch hazel mixed with a few drops of lavender oil can be used as a cooling compress.
• Bug repellent herbs include lavender, citronella, eucalyptus, and pennyroyal. Mix 15 drops of each essential oil with 1 oz. of food-grade oil (e.g., almond or olive). May need frequent application, tid to qid.

An experienced homeopath should assess individual constitutional types and severity of disease to select the correct remedy and potency. For acute prescribing use 3 to 5 pellets of a 12X to 30C remedy every one to four hours until acute symptoms resolve.

• Aconite for acute swelling with anxiety and fear.
• Apis mellifica for stinging pains with rapid swelling that feels better with cold applications. Patient is fatigued and apathetic.
• Belladonna for rapid, intense swelling with redness and heat. Patient is thirstless and calm.
• Ledum for puncture wounds, especially with coldness surrounding injury.
• Topical homeopathic preparations containing Ledum, Arnica, Calendula, Hypericum, and/or Urtica may provide symptomatic relief. Do not apply over broken skin.

Because biphasic anaphylactic episodes can occur, patients with significant hypotension or bronchospasm should be observed for 8 to 12 hours or admitted. Referral to an allergist is warranted with anaphylaxis.

• Venom immunotherapy for patients with systemic reactions reduces anaphylaxis risk to 1% to 2% if sting occurs during therapy; increase usual maintenance dose of 100 mcg to 200 mcg when treatment fails; risks include systemic reactions (observe patient for at least 20 minutes); treatment usually ends after three years (five years in severe cases) in spite of continued positive venom skin tests.
• Emergency insect stinging kits (EpiPen, Epi-EZ-Pen, Ana-Kit) have both epinephrine (1.6 to 4.8 mg) and antihistamines (e.g., diphenhydramine [Benadryl], 25 to 50 mg).
• Diethyltoluamide (deet) repels only biting insects; use concentration above 75%; toxic if ingested and may damage synthetic clothing.
• Citronella is an effective, nontoxic plant source; reapply frequently.
• Wear a Medic Alert bracelet if susceptible to systemic reactions.
• Keep bites clean, refrain from scratching to prevent secondary infection.
• Do not use scented hair oils or perfumes.
• Wear shoes and long pants, and no floral-patterned or dark clothing.

• Secondary infection from scratching and poor hygiene
• Excessive epinephrine—can cause hypertension and arrhythmia, especially with coexisting heart disease
• Reaction to venom immunotherapy (12% of patients)
• Encephalitis, vasculitis, renal failure, nephrotic syndrome
• Multiple stings can cause systemic toxic reaction in nonallergic patients and may be fatal.
• Biting insects may transfer disease (e.g., mosquitoes/malaria).

• 50% of patients have recurrent allergic reactions.
• Immunologic tests cannot predict subsequent urticarial reactions.
• Spontaneous remission is highest in children under age 16.

Large doses of vitamins and flavonoids are contraindicated in pregnancy. Small doses of vitamin C (500 to 1,000 mg tid) may provide relief. Topical preparations, excluding essential oils, are safe.

Habif TP. Clinical Dermatology. 3rd ed. St. Louis, Mo: Mosby-Year Book; 1996.

Kruzel T. The Homeopathic Emergency Guide. Berkeley, Calif: North Atlantic Books; 1992:198-200.

Middleton E, ed. Allergy: Principles and Practice. 5th ed. St. Louis, Mo: Mosby-Year Book; 1998.

Rakel RE, ed. Conn's Current Therapy. 50th ed. Philadelphia, Pa: WB Saunders Co; 1998.