Insect bites and stings
A number of insects, including bees, spiders, fleas, hornets, wasps, and mosquitoes can bite or sting. Some bites and stings cause itching; others cause pain. The itching and pain occur because the insect has injected venom or another irritating substance into your skin, which causes an allergic reaction. In most cases, this reaction is bothersome but not dangerous. However, a severe reaction can cause anaphylaxis, resulting in shortness of breath and tightening of your throat. Anaphylaxis can be fatal, even on the first reaction. Severe reactions can affect the whole body and may occur in minutes. This is a medical emergency and you should call 9-1-1. Another type of allergic reaction is called angioedema, which involves swelling throughout your body, especially the face, lips, and around the eyes. More people have allergic reactions to stinging insects than to biting insects.
Signs and Symptoms
- Red, swollen, warm lump
- Itching, tenderness, pain
- Sores from scratching; can become infected
Serious allergic reactions (called anaphylaxis):
- Difficulty breathing
- Muscle spasms
- Loss of consciousness
Stinging insects include bumblebees, yellow jackets, hornets, wasps, and fire and harvester ants. Biting insects include conenose bugs, mosquitoes, horseflies, deerflies, spiders, ticks, bedbugs, and black flies.
- Try not to provoke insects. For example, avoid rapid, jerky movements around insect hives or nests.
- Avoid perfumes, lotions, and scented soaps.
- Avoid areas where you know insects are.
- Use insect repellants and protective clothing.
- Be careful when eating outdoors, especially with sweet drinks (such as sodas), or in areas near garbage cans.
- Make sure you have screens on all windows.
- Keep mosquito eggs from hatching by removing standing water.
- Avoid being outside at dawn and dusk, when mosquitoes are most active.
- Use citronella, linalool, and geraniol candles. In one study, citronella candles reduced the number of female mosquitoes caught in traps by 35%; linalool candles reduced female mosquitoes by 65%; and geraniol candles reduced female mosquitoes by 82%.
If you know that you have a serious allergy to an insect, carry an emergency epinephrine kit, or Epi-pen. Your doctor can prescribe one. If you have had a reaction in the past, make sure that friends and family members know how to use an Epi-pen if you have had a reaction in the past. Wear a medical ID bracelet. For those with allergies, venom immunotherapy is up to 98% effective in preventing sting anaphylaxis.
If you are traveling to an area where malaria is common, ask your doctor about a malaria vaccine.
You can prevent insect bites and stings with proper clothing:
- Cover your head. Wear a full brimmed hat to help shield your neck as well.
- Wear long-sleeved shirts and long pants.
- Tuck pant cuffs into socks. This helps protect your ankles, a common spot for bites or stings.
- Check your clothes and hair periodically for bugs.
- Use protective netting when sleeping or eating outdoors.
Applying insect repellent to your clothes instead of your skin can help prevent irritation. When in an area infested with mosquitoes, sand flies, or ticks, use a chemical insect repellent such as permethrin or DEET. DEET is the most effective and broadly used insect repellent. DO NOT apply insect repellent to sunburned skin. When applying both sunscreen and bug repellent, apply sunscreen first. Wait 30 minutes before applying bug repellent.
DO NOT use bug repellent on children's hands because they may rub their eyes, or put their hands in their mouths.
In most cases, bites and stings can be easily treated at home. However, do not try to treat a suspicious bite on your own. When in doubt, call your doctor. In the case of a severe allergic reaction, such as anaphylaxis, you must seek emergency medical help. DO NOT try to treat anaphylaxis with complementary therapies alone. If such an emergency occurs:
- Check the person's airway, breathing, and pulse. If necessary, begin CPR and call 9-1-1.
- Use the person's Epi-pen or other emergency kit if they have one. (Anyone who has had a serious allergic reaction to an insect sting should carry an Epi-pen or its equivalent at all times.)
- Try to keep the person calm.
- Remove any rings and other constricting items in case of swelling.
- Stay with the person until medical help arrives.
Redness, minor swelling, pain, or itching at the site of the bite generally go away within 3 to 7 days with no treatment, even if the affected area is large. To relieve your symptoms, follow these steps:
- Remove the stinger if it is still present by scraping the back of a credit card or other straight edged object across the stinger. DO NOT use tweezers to pull out the stinger, that may release more venom.
- Wash thoroughly with soap and water to avoid infection. Watch for signs of infection, such as increased redness or red streaking along your skin, over the next several days.
- Place an ice pack, wet compress, or ice wrapped in a cloth on the site of the sting for 10 minutes, then off for 10 minutes.
- Take an antihistamine or apply a cream that reduces itching (such as Calamine or Benadryl ointment) if the bite itches. You can also use a paste made of 3 parts baking soda to 1 part water.
- Antihistamines can be used to reduce itching and swelling.
- Topical corticosteroids for persistent bite reactions.
- If you develop an infection at the site of the bite, your doctor may prescribe antibiotics.
- In case of a severe reaction, emergency medical personnel may give intravenous (IV) antihistamines, injected corticosteroids, and epinephrine (adrenaline).
Nutrition and Dietary Supplements
Including certain nutrients in your diet may help support your immune system and possibly reduce any inflammation or allergic reaction from an insect bite or sting. There is no scientific evidence that they will be effective, so talk to your doctor before taking a supplement to make sure that it is safe for you and will not interact with any medications that you regularly take. DO NOT treat serious reactions with nutrition and dietary supplements alone.
- Quercetin. A flavonoid and antioxidant found in many plants that may help reduce allergic reactions. The water-soluble kind of quercetin, sometimes called hesperidin methylchalcone (HMC) or quercetin chalcone, is more easily absorbed and has stronger effects for some people.
- Vitamin C. Supports immune system function and also enhances the effect of quercetin.
- Omega-3 fatty acids (fish oil). May help reduce inflammation in the body, so some experts think they might also protect against severe allergic reactions. In one study, there was a lower death rate from anaphylactic shock in animals on a high omega-3 fatty acid diet compared to those on a high omega-6 fatty acid diet. Researchers do not know if the effects would be true of humans. More studies are needed. Omega-3 fatty acids can have a blood-thinning effect and should be used with caution in people with bleeding disorders or who use blood-thinning medications. Talk to your doctor.
Few studies have examined the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for insect bites and stings based on his or her knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type, includes their physical, emotional, and intellectual makeup. An experienced homeopath assesses all of these factors when determining the most appropriate remedy for a particular individual. DO NOT treat serious reactions with homeopathy alone.
- Apis mellifica. For stinging pains with rapid swelling and an affected area that is warm to the touch; this remedy is most appropriate for individuals who feel better with cold applications; Apis is recommended if hives are present or if Ledum does not reduce pain or swelling after 4 hours.
- Hypericum. For bites accompanied by sharp, shooting pains that often occur in sensitive areas, such as at the ends of fingers or toes.
- Ledum. Most commonly used homeopathic agent for bites and stings from bees, mosquitoes, wasps, or spiders; affected area is cold to the touch but cold applications or immersion in cold water improves symptoms.
- Staphysagria. For children with large, itchy mosquito bites that may create large welts.
- Urtica urens. For red, swollen bites with itching and stinging; may be used instead of Apis to treat hives.
Some essential oils may help repel insects. Dilute the oil before applying it to your skin. Never apply pure essential oils directly. Avoid contact with your eyes. These oils include:
- Eucalyptus (Eucalyptus globulus)
- Clove (Eugenia caryophyllata)
- Citronella (Cymbopogon spp.)
- Neem oil or cream (Azadirachta indica)
- Camphor and menthol gels
Auerbach: Wilderness Medicine. 5th ed. Philadelphia, PA: Elsevier Mosby; 2007.
Aberer E. What should one do in case of a tick bite? Curr Probl Dermatol. 2009;37:155-66.
Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000;230-2, 379-34.
Boyle RJ, Elremeli M, Hockenhull J, et al. Venom immunotherapy for preventing allergic reactions to insect stings. Cochrane Database Syst Rev. 2012;10:CD008838(1469-93X).
Cavanagh HM, Wilkinson JM. Biological activities of lavender essential oil. Phytother Res. 2002;16(4):301-8.
Elston D. Bolognia: Dermatology. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012.
Fallatah SA, Khater EI. Potential of medicinal plants in mosquito control. [Review]. J Egypt Soc Parasitol. 2010;40(1):1-26. Review.
Ferri: Ferri's Clinical Advisor 2016. Philadelphia, PA: Elsevier; 2016.
Golden D. Insect Sting Anaphylaxis. Immunology and Allergy Clinics of North America. 2007;27(2).
Govindarajan M. Ovicidal and repellent properties of Coccinia indica Wight and Arn. (Family:Cucurbitaceae) against three important vector mosquitoes. Eur Rev Med Pharmacol Sci. 2011;15(9):1010-9.
Katz TM, Miller JH, Herbert AA. Insect repellents: historical perspectives and new developments. J Am Acad Dermatol. 2008;58(5):865-71.
Lukwa N, Molgaard P, Mutambu SL, Musana BJ. Seven essential oils inhibit Anopheles arabiensis mosquito biting. Cent Afr J Med. 2002;48(11-12):141-3.
Mikulak E, Gliniewicz A, Krolasik A, Sawicka B, Rabezenko D. Evaluation of effectiveness of several repellents against mosquito bites available at the Polish market. Przegl Epidemiol. 2012;66(3):479-85.
Mingomataj EC, Bakiri AH, Ibranji A, Sturm GJ. Unusual reactions to hymenoptera stings: what should we keep in mind? Clin Rev Allergy Immunol. 2014;47(1):91-9.
Moore S, Mordue A, Logan J. Insect Bite Prevention. Infectious Disease Clinics of North America. Philadelphia, PA: W. B. Saunders Company. 2012;26(3).
Morsy TA. Insect bites and what is eating you? J Egypt Soc Parasitol. 2012;42(2):291-8.
Mueller GC, et al. Ability of essential oil candles to repel biting insects in high and low biting pressure environments. J Am Mosq Control Assoc. 2008;24(1):154-60.
Nerio LS, Olivero-Verbel J, Stashenko E. Repellent activity of essential oils: a review. Bioresour Technol. 2010;101(1):372-8.
Oyedele AO, Gbolade AA, Sosan MB, Adewoyin FB, Soyelu OL, Orafidiya OO. Formulation of an effective mosquito-repellent topical product from lemongrass oil. Phytomedicine. 2002;9(3):259-62.
Pitasawat B, Choochote W, Tuetun B, et al. Repellency of aromatic turmeric Curcuma aromatica under laboratory and field conditions. J Vector Ecol. 2003;28(2):234-40.
PPAV Working Groups. Personal protection against biting insects and ticks. Parasite. 2011;18(1):93-101.
Tawatsin A, Wratten SD, Scott RR, Thavara U, Techadamrongsin Y. Repellency of volatile oils from plants against three mosquito vectors. J Vector Ecol. 2001;26(1):76-82.
Trongtokit Y, Rongsriyam Y, Komalamisra N, Apiwathnasorn C. Comparative repellency of 38 essential oils against mosquito bites. Phytother Res. 2005;19(4):303-9.
Wilson MD, Osei-Atweneboana M, Boakye DA, et al. Efficacy of DEET and non-DEET-based insect repellents against bites of Simulium damnosum vectors of onchocerciasis. Med Vet Entomol. 2013;27(2):226-31.
Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.