Bites and stings

Definition

A bite is an injury caused by an animal, such as a mammal or insect, that breaks the skin. A sting is a puncture wound made by insects or marine animals. There is often a danger of infection from toxins or venom with bites and stings.

Description

In the United States, dogs surpass all other mammals in the number of bites inflicted on humans. Children face a greater risk than adults, and children under 10 years old are more liable than anyone to suffer serious bites to the face, neck, and head. Cat bites are far less common than dog bites, but they carry a higher risk of infection. Bites from wild animals should be of especial concern due to the risk of rabies. More than 70,000 human-to-human bites a year are reported in the United States. Human bites are more infectious than those of any other animal.

The most common invertebrates responsible for bites and stings include lice, bedbugs, fleas, mosquitoes, black flies, fire ants, chiggers, ticks, centipedes, scorpions, spiders, bees, and wasps. Black widows and brown recluse spiders are the two most common poisonous spiders in the United States. The bites of most other spiders in North America cause only minor reactions. Ticks attach themselves to the skin and feed on the blood of animals. Most are relatively harmless, but some carry diseases such as Rocky Mountain spotted fever and Lyme disease. Now, people worry about the danger or West Nile virus from mosquito bites. Bees and wasps will sting to defend their nests or if they are disturbed. Fifty or more people a year die in the United States after being stung by bees, wasps, or fire ants. Almost all of those deaths are the result of allergic reactions.

The poisonous snakes of the United States are divided into two families, pit vipers (which include rattlesnakes, copperheads, and cottonmouths, also called water moccasins) and the coral snake family. Pit vipers are responsible for about 99% of the poisonous snakebites in the United States. Each year about 8,000 people in the United States fall victim to a venomous snakebite. However, only about 15 of those people die. Most deaths are due to rattlesnake bites. In comparison, coral snakes are responsible for about 25 bites a year in the United States.

Jellyfish, stingrays, sea urchins, sea anemones, barracudas, and coral pose a threat to those who live or vacation in coastal communities. The majority of stings received from marine animals happen in saltwater and are rarely life-threatening.

Causes & symptoms

The typical animal bite results in a laceration, tear, puncture, or crush injury. Cat bites are mostly found on the arms and hands, with deep puncture wounds that can reach to muscles, tendons, and bones. Human bites result from fights, sexual activity, and seizures. They may also be due to spousal or child abuse. Children often bite other children, but those bites are hardly ever severe. Human bites are capable of transmitting a wide range of dangerous diseases, including hepatitis B, syphilis, and tuberculosis.

People do not always feel a spider bite. In most cases, spider bites produce only minor symptoms. The first, and possibly only, evidence of a bite may be a mild swelling of the injured area and puncture marks or blisters. The affected area may be painful, itchy, or discolored. With more serious bites, there may be severe muscle cramps and rigidity of the abdominal muscles shortly after being bitten. Other possible symptoms include excessive sweating, nausea, vomiting, headaches, fever, chills, edema, and dizziness, as well as problems with breathing, vision, and speech. In addition, a brown spider's bite can lead to necrotic arachnidism, in which the tissue around the bite dies. This can produce an open sore that that can take years to heal completely. The symptoms of bee and wasp stings include pain, redness, swelling, and itchiness at the area of the sting. Multiple stings can have much more severe consequences. The danger signs of a severe allergic reaction, called anaphylactic shock, need immediate medical attention. They include nausea, chest pain, abdominal cramps, diarrhea, and difficulty swallowing or breathing.

Venomous pit viper bites usually begin to swell within 10 minutes and sometimes are painful. Other symptoms include edema at the wound site, skin blisters and discoloration, weakness, sweating, nausea, faintness, dizziness, bruising, and tender lymph nodes. Severe poisoning can lead to tingling sensations, muscle contractions, an elevated heart rate, rapid breathing, large drops in body temperature and blood pressure, vomiting of blood, and coma. Coral snake bites are painful, and the effects of the venom may include tingling at the wound site, weakness, nausea, vomiting, excessive salivation, and irrational behavior. Nerves can become paralyzed, causing double vision, difficulty swallowing and speaking, and respiratory problems. Poisonous snakes often introduce little or no venom into the victim's body when they bite. The symptoms of these bites are not so severe. However, there is still a danger that the wounds can become infected by harmful microorganisms from the snake's mouth.

Jellyfish venom is delivered by barbs located on their tentacles. These barbs can penetrate the skin of people who brush up against them, even if the jellyfish is dead or the tentacle is severed from the body. Painful and itchy red lesions arise instantly on contact. The pain can continue up to 48 hours. Severe cases may lead to skin necrosis, muscle spasms and cramps, vomiting, nausea, diarrhea, headaches, excessive sweating, and other symptoms. In rare cases, jellyfish venom may cause cardiorespiratory failure.

Tail spines are the delivery mechanism for stingray venom. Stingray venom produces immediate, excruciating pain that lasts several hours. They cause deep puncture wounds, which may become infected if pieces of the spines become embedded in them. Sometimes the victim suffers a severe reaction, including vomiting, diarrhea, hemorrhaging, a drop in blood pressure, and cardiac arrhythmia.

Signs of infection in a bite or sting site include redness, pain, swelling, warmth, and a discharge filled with pus. An inflammation of the connective tissue, called cellulitis, may also result. Sometimes systemic, and possibly life-threatening, infections develop, especially among those who are immunosuppressed.

Diagnosis

Most bites and stings are minor and do not need to be formally diagnosed. When required, though, diagnosis relies on a physical examination of the victim, information about the circumstances of the injury, and a look at the animal that caused the injury, if possible. It is especially important to retrieve the live animal or carcass of dogs, wild animals, snakes, and spiders for assessment. Information about tetanus immunization history and possible allergies to venom is important. A physical exam may be required to assess damage caused by deep puncture wounds or severe crush injuries. Chest x rays and electrocardiography may be required to assess severe symptoms. Laboratory tests for identifying the microorganisms may be ordered if there is an infection. Blood and urine tests also may be taken. Testing the blood for hepatitis B and other diseases is always necessary after a human bite, for example. Medical professionals should also look for indications of spousal or child abuse in cases of human bites.

Treatment

Some bites and stings, such as those from venomous snakes, require immediate medical attention, as do a host of others. So often, it is best to check with a medical/emergency practitioner first. Also, once a patient begins treating a bite or sting with an alternative method, if signs of infection or severe allergic reaction appear, he or she should seek immediate medical help.

Homeopathic remedies can be useful for relieving the pain and swelling of bites and stings. If there is a possible allergic reaction, these remedies can be used while awaiting emergency care. Aconitum can be helpful, especially if the person feels fearful or panicked after being stung. Aconitum should be used while symptoms are intense, and then can be followed a by another remedy, as indicated. Apis mellifica is especially useful for bee stings, and it can help to reduce the allergic reaction. Carbolicum acidum can also be used to treat an allergic reaction, especially when the person feels sick and weak and has trouble breathing. Cantharis, Ledum palustre, Hypericum, and Urtica urens are other useful remedies that may be indicated. A 6c or 12c dose of the chosen remedy can be taken every 15 minutes for up to four doses.

Neem, an Ayurvedan remedy, can be used to soothe minor bites and stings as well as to keep insects away. A thick paste can be made from neem powder blended with warm water. It can then be applied to the affected area twice daily. To prevent insect bites altogether, neem oil can be rubbed on exposed skin as a repellant. Another Ayurvedic remedy for soothing insect bites uses the herb cilantro. One cup of the fresh leaves should be mixed with 1/3 cup of water in a blender and strained. The juice should be stored in the refrigerator, and 2 tbsp can be taken three times per day. The pulp should be saved and applied directly to affected areas once or twice daily.

A compress made from meat tenderizer that contains either papain or bromelain breaks down the venom of bites and stings. This is because most venom is protein-based. The meat tenderizer functions by breaking down such proteins, which neutralizes the venom. A thick paste can be made using warm water or rubbing alcohol and powdered meat tenderizer and then applied directly to the affected areas for relief. Powdered bromelain or papain can also be used. The typical home's kitchen or medicine cabinet holds quick soothers for bee and wasp stings. Bicarbonate of soda or ammonia can soothe a bee sting and vinegar or lemon juice have been shown to help soothe wasp stings.

Allopathic treatment

Minor animal bites can be treated at home. The wound should be washed with soap and water. Applying pressure to the injured area with a clean towel or sterile bandage can stop bleeding. Antibiotic ointment and a sterile dressing can be applied to the wound if necessary. Alternately, to minimize swelling and infection, ice can be applied to the wound. Bites that do not stop bleeding after 15 minutes with pressure should be seen by a medical professional. Medical attention may also be required if there are signs of infection. People who have been bitten by a cat or by a human should always see a doctor. The same is true for snake bites; bites that are deep or gaping; bites to the head, hands, or feet; and bites that may be in conjunction with broken bones, damaged nerves, or any other major injury. If an unfamiliar animal bites, especially for no apparent reason, rabies may be suspected. A physician should be consulted. Dogs, raccoons, skunks, bats, coyotes, foxes, and ground hogs often carry rabies. In cases of suspected rabies, the victim will be given several injections with rabies vaccine. Diabetics, AIDS patients, cancer patients, people who have not had a tetanus shot in five years, and anyone else who has increased susceptibility to infection should also seek medical treatment for all bites and serious sting wounds.

Medical treatment may require the removal of dead and damaged tissue. Any patient whose tetanus shots are not up-to-date should receive a booster shot. Some wounds are left open and allowed to heal on their own, while others may require stitches. Antibiotics are usually limited to patients whose injuries or other health problems make them likely candidates for infection. Cat bites and human bites, however, are usually treated with antibiotics. The patient may also require immunization against hepatitis B and other diseases. A follow-up visit could be required.

An ice pack should be applied to the area of a spider bite as soon as it is discovered. Treatment for a serious spider bite may involve the administering of muscle relaxants, antihistamines, antibiotics, pain medication, and possibly a tetanus shot. Areas of necrosis may need debridement and skin grafts. An antivenin is available, but it is not necessary in most cases, and could possibly cause unpleasant side effects.

Most stings can be treated at home. A stinger can be scraped off the skin with a blade, fingernail, credit card, or stiff piece of paper. Tweezers are not recommended, since they may actually push more venom into the wound. The area should then be cleaned and covered with ice. Aspirin and other painkillers, antihistamines, and calamine lotion are good for reducing symptoms. People who experience an allergic reaction, or who are at risk for one, should seek immediate medical attention. People who are allergic should carry emergency kits containing epinephrine to counter anaphylactic shock at all times. Ticks can be carefully removed at home using tweezers. It is important to be sure that the head of the tick is not left embedded in the skin. If symptoms such as fever, rash or pain develop after a tick bite, a physician should be consulted immediately.

Although most snakes are not poisonous, any snakebite should immediately be examined at a hospital. If there is time, the victim should wash the wound site with soap and water, and then keep the injured area still and at a level lower than the heart. The injured person should not have anything to eat or drink, especially alcohol, until an evaluation and treatment is obtained. There is controversy about the use of tourniquets as well as sucking out venom. These should only be done when help is far away and by someone familiar with first aid techniques. Minor rattlesnake bites can be successfully treated without antivenin, as can the bites of copperhead and water moccasins. However, coral snake and the more dangerous rattlesnake bites require antivenin. Other treatment measures include antibiotics to prevent infection and a tetanus booster shot.

When dealing with bites or stings of marine animals, the victim should be kept still. Gloves should be worn when removing stingers. The area should be washed with saltwater and then soaked in very hot water for 30-90 minutes to neutralize the venom. Vinegar and other substances are used to neutralize jellyfish barbs, which are then scraped off. A doctor will usually examine stingray wounds to ensure that no pieces of the spines remain. Anesthetic ointments, antihistamine creams, and steroid lotions are sometimes beneficial. If the bites or stings are severe, they may require emergency care.

Expected results

Most bites and stings require little intervention, and clear up in a few hours or days. Those most at risk of severe problems with bites and stings are very young children, the elderly, those who are immunosuppressed, and people who are allergic to venom. Serious bites and stings require prompt treatment to ensure a favorable outcome. Infected bites may require hospitalization and can be fatal if neglected. In some cases, medication and surgery may be necessary. Some snakebites may result in amputation, permanent deformity, or loss of function in the injured area. People who are allergic to stings may experience a severe, and occasionally fatal, reaction.

Prevention

Insect repellant can help prevent insect bites and stings. Those with concentrated amounts of DEET stay effective longer. Sweet-scented fragrances should be avoided. Wearing white or khaki-colored clothing, including socks and long pants, helps protects the skin from bites or stings. Care and attention should always be used when going into wilderness areas. Posted warnings in swimming areas should be heeded. Unfamiliar animals should not be touched. Dead or dying animals should be avoided, as they may still be able to cause injury. When threatened by a dog, a person should remain still. If an attack seems unavoidable, lying face down with the hands and forearms covering sensitive areas may be the best protection. A rabies vaccine may be taken preventively if there is a high risk of exposure due to work or travel.

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