Insect bites and stings are a common source of injury to the skin that typically results in a small, red and itchy bump.

In rare cases, bites and stings can result in complications, such as infection or a severe and life-threatening allergic reaction called anaphylactic shock. Numerous small creatures, classified as both insects and arachnids (e.g., spiders, ticks, mites), can bite or sting. Those that bite include mosquitoes, ticks, fleas and spiders. Those that sting include honeybees, wasps, yellow jackets and scorpions.

Symptoms are usually mild and disappear within a few hours or days. They may include redness, itching and mild pain at the site of the bite or sting. Symptoms of patients experiencing a severe allergic reaction may include difficulty breathing, rapid heart rate and hives. Patients experiencing symptoms of an allergic reaction should seek medical treatment immediately.

Most insect bites and stings do not require a visit to a physician. However, in some cases, a physician may determine the type of insect bite or sting experienced by a patient during a physical examination.

Most bites and stings can be treated at home in a variety of ways, such as antihistamine lotions and over-the-counter analgesics (pain relievers). Patients experiencing allergic reactions are usually treated with an injection of epinephrine (adrenaline) that helps reverse symptoms.

There are several ways to prevent insect bites and stings, such as using insect repellant, wearing light-colored clothing that covers skin areas and keeping food covered until it is eaten when dining outdoors.

Insect bites and stings are a common source of injury to the skin, particularly during warm weather when outdoor activities are popular. Insects bite because they require human or animal blood for food or to produce eggs. An insect may sting when it feels threatened and is trying to defend itself.  

Although generally referred to as insect bites or stings, many such injuries are caused by creatures other than insects, including various arachnids (e.g., spiders, ticks, mites). When the skin is bitten or stung, the insect or arachnid injects saliva or venom. In most cases the body’s immune system reacts mildly to the saliva or venom, typically resulting in a small, red and itchy bump that disappears within a few hours or days. However, some patients develop large sores (ulcers) with pain and swelling.

Most bites and stings do not require emergency medial treatment, although young children and the elderly may be more affected by bites and stings.

In some cases, bites and stings can result in a variety of complications, including:

• Dermatitis. An inflammation of the skin that can have many causes and occur in many forms. The term usually describes skin that is swollen, red and itchy and can be an allergic reaction. It is neither life threatening nor contagious.
  
  

  

• Other allergic reactions. A mild allergic reaction may result in nausea, swelling and other discomforts. In rare cases, an insect sting can result in a severe, potentially life-threatening allergic reaction known as anaphylactic shock. This can impair breathing and heart function, leading to death in some people.
  
  
• Infection. Some insect bites can cause bacterial infections, such as impetigo, a contagious superficial skin infection produced when bacteria commonly present on the skin enter through the bite opening. If not treated properly, cellulitis, a skin infection of the deeper layers of the skin characterized by redness, swelling and pain, may occur.
  
  
• Disease. Some insects carry bacteria or viruses. Some of the most common diseases caused by bites and stings include:
  
  
• • Lyme disease. An infectious disease spread by bacteria-carrying ticks. Symptoms can be as mild as a rash at the bite site, fever and chills and as serious as muscle paralysis, severe arthritis or heart and neurological disorders in the late stages of the disease.
    
    
  • West Nile virus. A disease primarily spread through the bite of an infected mosquito that affects the central nervous system in humans and animals. Mosquitoes become infected when they feed on infected birds. Most people infected with the virus experience no symptoms, although some may experience flu-like symptoms. Some severe cases have resulted in death.
    
    
  • Rocky Mountain spotted fever. A rare bacterial disease transmitted to humans through the bites of ticks. It is characterized by small pink spots on the wrists and ankles that spread to other parts of the body, become larger and bleed.
    
    
  • Malaria. An infectious parasitic disease transmitted by the bite of an infected female mosquito. It includes cycles of chills, fever and sweating. Malaria causes millions of deaths worldwide in tropical areas, although it is extremely rare in the United States.
    
    
  • Dengue fever. An infectious viral disease found in tropical climates that is transmitted by mosquitoes and characterized by rash, fever, sore throat and aching head and joints.
    
    
  • Encephalitis. An inflammation of the brain, often caused by a viral infection. Exposure occurs through insect bites, food or drink, or skin contact. Travelers are most at risk from insect bites.

There are many types of small creatures that bite. They include insects and arachnids (e.g., spiders, ticks, mites). The most common ones in the United States include:

• Mosquitoes. There are about 200 different species of mosquitoes in the United States. Mosquitoes tend to breed in damp areas of standing water, such as stagnant ponds or swimming pools.
  
  
• Ticks. Ticks usually live in woods, tall grass, weeds and brush. They climb onto low vegetation and attach to passing hosts, including people and animals. Most tick bites in the United States are from species that will attach themselves and feed for several days unless removed.
  
  
• Mites. Mite bites are more common outdoors, as house mites do not bite. Chiggers (mite larvae that feed in the skin) are found everywhere outdoors except in arid (dry) regions.
  
  
• Fleas. Wingless, blood-sucking insects that feed on dogs, cats, humans and other species. They prefer dogs and cats, but in their absence, will use humans or other available animals as hosts.
  
  
• Lice. Tiny, wingless parasitic insects that feed on blood. There are several types that infect humans including head lice, body lice and pubic lice.
  
  
• Flies. Though the common house fly does not bite, many other types of flies do, including sand flies, horseflies, deerflies, blackflies and stable flies.
  
  
• Bugs. There are several different types of bugs that bite including bedbugs, wheel bugs, kissing bugs and certain water bugs.
  
  
• Black widow spiders. Only the bite of females is poisonous. They are usually about 2 inches (5 centimeters) across, long-legged, shiny and coal black. They also have an orange, red or yellow shape on their underside that normally resembles an hourglass. They are found throughout the United States.
  
  
• Brown recluse spiders. Also known as fiddle spiders, they are 1/2 inch (1.2 centimeters) long with a dark, violin-shaped mark on the combination head and middle section (cephalothorax). Brown recluse spiders are most often found in the south central United States. They live in hot, dry undisturbed areas, such as wood or rock piles.
  
  
• Hobo spiders. A light-brown spider with a yellowish green tint on its abdomen. Roughly 1/2 inch (1.2 centimeters) long, it lives in funnel webs spun in wood, rock or debris piles. They can be found in Alaska, Oregon, Idaho, Montana, Utah and British Columbia.
  
  
• Tarantulas. Large, hairy spiders that live in warm areas. Bites are rare, but can be painful.

Other groups of insects and arachnids can sting. Insects that sting are members of the order Hymenoptera of the class Insecta. There are two major subgroups: apids (honeybees and bumblebees) and vespids (yellow jackets, wasps and hornets). Fire ants are wingless members of Hymenoptera. Some types of insects, such as bees, only sting when they are provoked. Others, such as yellow jackets, are more aggressive. Fire ants attack people who walk on their nests.

Stinging creatures include:

• Bees. Roundish, fuzzy bodies with dark brown coloring and yellow markings. Some common types of bees are honeybees and bumblebees. Honeybees are the most common of stinging insects. They are found near clover and around flowers. Bees often leave a barbed stinger inside their victims.
  
  
• Yellow jackets. Black bodies with yellow markings and slimmer than honeybees. Yellow jackets are the most aggressive of stinging insects and sting repeatedly. They are found around garbage cans and anywhere food is exposed, especially sugary foods.
  
  
• Wasps. Black, brown or red bodies with yellow markings. These vespids are slender, hairless and elongated. Wasps build nests in the eaves of buildings and under rafters. They sting repeatedly.
  
  
• Hornets. Larger than yellow jackets, with short black or brown bodies and white, orange or yellow markings. They are found in trees and bushes and sting repeatedly.
  
  
• Fire ants. Reddish brown or black bodies. They are found in the southeastern United States. Fire ants use their mandibles (lower jaws) to bite into the skin, which anchors them. Then, they use a hind stinger to produce multiple stings in a circular pattern that burn fiercely.
  
  
• Scorpion. Arachnid similar to spiders with eight legs. The species found in the United States are relatively safe and stings (which are rare) are likened to wasp stings.

Symptoms usually begin to develop immediately following an insect bite or sting. In most cases, they are mild and disappear within a day or two. Symptoms may include:

• Wound
• Mild pain
• Redness
• Swelling
• Itching
• Burning
• Numbness
• Tingling
• Rash
• Headache

Insects that sting leave their stinger in the flesh, which may be visible. Ticks attach to skin for several days and may still be visible at the site of the tick bite.

Symptoms of an allergic reaction to an insect sting may appear right away, or may be delayed as much as four hours to a week later. Symptoms of a mild allergic reaction to an insect sting include:

• Mild nausea
• Cramps
• Hives

• Itching (pruritus)
• Tenderness
• Diarrhea
• Red, warm, swollen lump more than 2 inches (5 centimeters) in diameter at the sting or bite site

A severe allergic reaction can be a life-threatening condition called anaphylaxis. Its symptoms may include:

• Intense itching, including areas other than the bite/sting site
• Feeling anxious
• Palpitations (an awareness of a strong, fast, irregular, abnormal or "galloping" heartbeat)
• Slurred speech
• Inability to swallow
• Swelling of the throat or tongue
• Rapid or weak pulse
• Red or swelling skin
• Hives (including on the lips, eyelids, throat and tongue)
• Cramps
• Diarrhea
• Nausea or vomiting
• Wheezing
• Bluish tint to skin (cyanosis), including lips or nail beds
• Coughing
• Choking
• Nasal congestion
• Difficulty breathing

Most cases of anaphylaxis involve either cardiovascular or respiratory symptoms, or both. More advanced symptoms of a severe allergic reaction may include:

• Collapse or loss of consciousness
• Convulsions
• Loss of bladder control
• Shock
• Stroke
• Cardiac arrest
• Respiratory arrest

Individuals experiencing severe allergic reaction or anaphylaxis require immediate medical attention.

Bites from some varieties of spider (which are arachnids, not insects) can lead to symptoms similar to a severe allergic reaction. Most spider bites are harmless. However, anyone who believes they may have been bitten by a poisonous spider should immediately contact a physician. Symptoms of such bites may vary depending on the type of spider, as follows:

• Black widow spider. Most who are bitten experience sharp pain and swelling at the bite site, which usually features two small fang marks. However, more serious symptoms can appear within 30 to 60 minutes and require immediate emergency medical attention. These include:
  
  
• • Deep blue or purple area around the bite, surrounded by a whitish ring and a large outer red ring
    
    
  • Muscle cramps and spasms at the bite site that increase and spread for 24 hours
    
    
  • Chills, fever, nausea and vomiting
    
    
  • Severe abdominal pain
    
    
  • Seizures
    
    
  • Stupor, restlessness and shock
    
    
  • Severe high blood pressure
    
    
• Brown recluse spider. Bites produce reddened skin and a blister at the bite site. Mild to intense pain and itching can follow for two to eight hours. An open sore with breakdown of the tissue (necrosis) also can develop within a few hours or days. This blackened tissue can take months to heal. Patients should seek medical care for necrosis, or any of the following symptoms:
  
  
• • Fever and chills
  • Skin rash over the body with tiny, flat purple and red spots
  • Nausea and vomiting
  • Joint pain
    
    
• Hobo spider. Symptoms include reddened skin that blisters within 36 hours. Numbness and tingling around the bite are common. About half of those bitten develop necrosis. Patients should see a physician if they develop necrosis or the following symptoms:
  
  
• • Headache
  • Weakness
  • Drowsiness
  • Vision problems
  • Hallucinations

Many types of insect bites and stings do not require a visit to a medical professional. However, patients whose symptoms persist, or who suspect they have had an allergic reaction to a bite or sting, should consult a physician, such as a dermatologist (physician who specializes in the treatment of skin, hair and nails).

To determine whether a bite or sting is responsible for prolonged symptoms, or whether an allergic reaction has occurred, a physician may conduct a physical examination and collect the patient's medical history, including a list of medications. Physicians may look at the pattern and location of bites to help identify the creature responsible for them.

Physicians may also perform an allergy skin test to pinpoint the source of the bite or sting. This is usually unnecessary; moreover, it carries the small risk that the patient may have an anaphylactic (allergic) reaction to the testing.

Many types of insect bites and stings can be treated at home and do not require a visit to a physician. There are several methods to prevent infection, and to relieve pain and itching (pruritus) due to common insect bites and stings. They include:

• Apply a cold or ice pack to a bite or sting for 15 to 20 minutes once an hour for the first six hours. Do not apply ice directly to the skin. Use a barrier, such as a towel, instead.
  
  
• Elevate the affected area to decrease swelling.
  
  
• Take an over-the-counter analgesic to relieve pain and swelling.
  
  
• Use an antihistamine (available in lotion and pill form) to relieve pain, swelling and itching.
  
  
• Use a hydrocortisone cream or calamine lotion applied directly to the skin to relieve itching and redness.
  
  
• To prevent infection, take the following steps:
  
  
• • Wash the affected area with soap and water.
    
    
  • After washing, wipe the affected area with rubbing alcohol or an antiseptic solution.
    
    
  • Trim fingernails to prevent scratching, which can lead to infection.
    
    
  • Avoid bursting any blisters that may develop.

The redness, swelling, pain and itching associated with most insect bites and stings subside on their own within three days to a week. However, patients should consult a physician if:

• New symptoms develop
• Signs of a skin infection develop, such as increasing redness, swelling or pain
• Flu-like symptoms develop
• Symptoms become more severe or frequent

For patients experiencing the severe allergic reaction known as anaphylaxis, the most effective way to reverse symptoms is with an injection of epinephrine (adrenaline). The drug relaxes the smooth muscle tissue in the lungs, speeds up the heart rate, slows the appearance of hives and welts on the skin and reduces overall swelling.

People with known allergies to bites and stings may be prescribed an allergy kit that includes an auto-injectable dose of epinephrine. Even if a self-administered dose of epinephrine successfully reverses symptoms, an individual should still seek immediate medical care. In about 10 percent of cases, anaphylactic symptoms recur. Antihistamines and corticosteroids may be prescribed to help reduce the chance of additional symptoms.

Other treatment tips include:

• Bees may leave behind a stinger attached to a venom sac. The stinger should be removed as quickly as possible with a blunt-edged object, such as a fingernail or credit card. Tweezers should not be used to remove stingers because they can squeeze the venom sac. This can increase the amount of venom released into the skin and add to the swelling and pain in the area.
  
  
• Stings anywhere in the mouth require immediate medical attention because the sting may cause swelling that can result in blocked airway passages.
  
  
• Fire ants should be brushed off to prevent repeated stinging. These wounds usually will blister, become cloudy and appear pustular within 24 hours. The wound should be cleaned with soap and water and left alone. It will heal in one to two weeks.
  
  
• Patients who suspect a black widow or brown recluse spider bite should seek emergency medical treatment.
  
  
• For tick bites, the tick should be removed with tweezers if it is still attached to the skin. The tick should be pulled straight out with steady pressure, not twisted or squeezed. Save the tick (to show the physician) and watch for signs of Lyme disease (e.g., rash, fever, chills) over the next two weeks. Medical help should be sought if the tick cannot be completely removed. Removing the tick promptly reduces the risk for disease.

A number of steps can be taken to prevent insect bites and stings, including:

• Use insect repellants to avoid insect bites before going into the woods or other areas where insects are found. Most authorities recommend using a repellent that contains DEET (N, N-diethyl-meta-toluamide). Make sure to follow directions on repellants. Some types are meant to be used only on clothing, not skin. A lower concentration repellant should be used on children. Pregnant women should avoid using a repellant that contains DEET.
  
  
• Wear clothing that covers the skin, such as long pants and long-sleeved shirts while outdoors. Tucking the cuffs of pants into socks can also help prevent bites and stings on the ankles. Do not wear flowery or bright-colored clothing or dark clothing. Whites and light colors are best. Avoid loose-fitting clothing, which can trap insects between the material and the skin.
  
  
• Avoid wearing perfumes, colognes, fragrant lotions, aftershave or scented hair products while outdoors because they may attract insects.
  
  
• Avoid spending time outdoors between dusk and dawn, if possible. Mosquitos are most active during this time of day.
  
  
• Check clothing for insects from time-to-time.
  
  
• Stick to main paths and avoid brushy, wooded and grassy places when possible.
  
  
• Check the body for ticks after spending time in woods, tall grass, weeds and brush. Ticks are often found between the toes, behind the knees, along the hairline, behind the ears, on the neck and in the groin and armpits.  
  
  
• Shower after vigorous exercise. Perspiration can make bees more aggressive.
  
  
• Avoid walking barefoot, especially in grass. The majority of honeybee stings are the result of stepping on the bees while walking without shoes.
  
  
• Keep window and door screens in good repair. Fix holes and ensure that the screens are tightly attached.
  
  
• Keep car windows closed to prevent insects from flying inside.
  
  
• Use protective netting while sleeping outdoors.
  
  
• Empty stagnant pools of water in swimming pool covers, rain gutters, ceramic pots, birdbaths and other areas because mosquitoes breed in standing water.
  
  
• Avoid disturbing sites that might host hives, such as large trees, stumps, logs and large rocks.
  
  
• If a bee colony is disturbed, those nearby should run for cover immediately. Running in a zig-zag pattern may help. If a colony of bees approaches, cover the face and head as much as possible to avoid stings in those particularly sensitive areas.
  
  
• Hire an exterminator to destroy hives or nests.
  
  
• Avoid swatting at insects or flailing the arms around them because this may provoke them. Instead, retreat slowly and calmly when insects appear threatening.
  
  
• When eating outdoors, keep all food covered until it is ready to be eaten.
  
  
• Avoid areas with open food containers, such as garbage cans, picnic areas and dumps.
  
  
• When outdoors, do not drink from cans or straws unless the inside of them can be seen. Yellow jackets may hide there.

Those who have had severe allergic reactions to bites or stings in the past should take the following additional steps:

• Keep an allergy kit prescribed by a physician. The kit should be kept handy at all times, but particularly while outdoors.
  
  
• Wear a medical identification tag to inform others of an insect allergy.
  
  
• Consider getting allergy shots (immunotherapy) to control or prevent symptoms. The goal of immunotherapy is to build up a patient’s tolerance to an allergen by giving them increasing, controlled doses of the allergen.

Preparing questions in advance can help patients have more meaningful discussions with physicians regarding their conditions. Patients may wish to ask their doctors the following questions about insect bites and stings:

1. Do my symptoms indicate an insect bite or sting?
   
   
2. What type of insect may have bitten/stung me?
   
   
3. How can I tell whether I am allergic to an insect bite or sting?
   
   
4. Does my insect bite/sting put me at risk for disease or other complications?
   
   
5. What steps can I take to relieve the itchiness?
   
   
6. When should I consult a physician after an insect bite or sting?
   
   
7. What symptoms would indicate that my wound has become infected?
   
   
8. How can I prevent the wound area from becoming infected?
   
   
9. What are some of the ways I can prevent insect bites and stings?
   
   
10. What biting or stinging insects are common in our area?
    
    
11. What insect bite-related diseases are common in our area?