Many insects have a venomous sting that can trigger allergic reactions in some people. Even those who are not allergic to the venom can experience symptoms such as redness, swelling and pain after a sting. The most common insects that sting found in the USA are wasps, hornets, honeybees, yellow jackets or fire ants.
A typical insect sting will cause redness and swelling at the location. However, people who develop an allergic reaction to the venom can have very serious symptoms. Stings can even cause anaphylaxis, which is potentially lethal.
It is very important to understand the differences between an allergic reaction and the normal effects of a sting. The right diagnosis can calm you down after a bite or help you get ready for a very dangerous situation, if you have a strong reaction.
Allergic reactions are caused by our immune system, which reacts too strongly to some external factors known as allergens. In the case of insect stings, the allergen is venom. Many insects can inject venom but five particular ones are commonly found and cause strong reactions.
Yellow jackets are a variety of wasps that live in various zones and have the typical black color with yellow stripes. They usually build large nests underground but smaller ones can be found in woodpiles or wall cracks.
Honeybees have been domesticated but can also live in the wild. They have a rounder shape, with a dark brown color and yellow markings. They build their honeycombs in locations that offer partial shelter, such as trees or old tires.
Another common variety of wasp is the paper wasp. They have thinner bodies with a variety of colors, including black, yellow, brown and red. Paper wasps build distinctive round nests in shrubs, piles of wood or under roofs.
Hornets are larger in size and their bodies are similar to yellow jackets. They can be brown or black, with markings of various colors: yellow, white or orange.
Fire ants are usually found in hot climates, where they build large mounds. They have a red or brown color and attack aggressively without warning to protect their home. They can swarm intruders with their large numbers and their venom can lead to serious pain.
Insects use their venom for various purposes. It is usually a weapon for self-defence but they also employ it to paralyze their prey. Insects use their stinger to inject venom under the skin, which reaches the blood stream and is eventually carried by dilated blood vessels all around the body. The venom is detected by nerve cells, which alert the immune system. When the immune system reacts with too much force, it can lead to a wide range of problems.
Mild allergic reactions are common and can have one or multiple symptoms around the location of the bite. These can include redness, itching, swelling, a burning sensation, pain or spots similar to pimples.
Anaphylactic reactions are quite rare and represent the severe form of allergies. They should be treated very seriously, since such reactions can be lethal. One or more of these symptoms can be present: swelling of the face, throat, or mucous tissues inside the mouth, increased pulse, sudden drops of blood pressure, dizziness, difficult breathing, swollen neck that hampers swallowing, red itchy rashes with hives that rapidly expand starting from the sting area, anxiety or restlessness. Since anaphylactic reactions are extremely dangerous, you should seek emergency medical treatment immediately.
In most cases, an insect sting doesn't trigger any allergic reaction at all. The venom will still cause the area around the bite to become red and swollen, with local itching or pain. It is normal for some swelling to occur, which doesn't mean it is an allergic reaction. In most cases, you don't have to worry and home local treatment is enough. Clean the area of the sting and apply disinfectant as well as some ice. Itching can be reduced by antihistamines, while local corticosteroid creams can be applied to relieve swelling.
Large local reactions have more serious symptoms but are not of an allergic nature. They usually cause extensive swelling, which persists for 2 to 7 days. Sometimes, the stung person also experiences vomiting or nausea. About one in ten stings cause a large local reaction. If the sting location becomes infected, a cure of antibiotics is required.
Allergic reactions are not limited to the local sting area, but become systemic and affect the entire body. This happens in a low number of cases, approximately 0.3-3% of all stings. The cause is an overreaction of the immune system of people who have already been exposed to the venom and have developed antibodies against it.
The easiest way to reduce the risk of an allergic reaction is simply to avoid stings completely. Kids should be educated from an early age to avoid insects in order to prevent bites. Teach them not to walk barefoot on grass, to check cups and straws for the presence of insects before drinking, to keep food covered in the open and avoid using open cans of sweet drinks like soda and juice, as well as play away from flowers beds and other locations with many insects.
Several items can attract insects, such as clothes with flowers or bright colors, perfumes and other body cosmetics with a strong fragrance. If you find an insect nest, call an exterminator and don't try to eliminate it on your own. When you are close to insects that can sting, stay as calm and quiet as possible and avoid arm-waving or other sudden movements. Just back off, as slowly as possible. Wooded areas have a large number of dangerous insects so cover as much of your skin as you can. Wear long pants, shirts with long sleeves and shoes with closed toes. If your clothes are too lose, insects can enter between them and the skin.
In any severe case of allergic reaction, doctors focus on maintaining the vital functions of the body, which are blood pressure and breathing. Oxygen can be administered using a facial mask to people who breathe with difficulty. In even more severe cases, a mechanical ventilator is a possible solution. This is just a temporary measure in cases of serious distress, only until the effects start to decrease.
In cases of too low blood pressure, doctors can decide to mount an IV line. Saline solutions administered through this line are able to increase blood pressure. Several drugs are also available, to regulate both breathing and the blood pressure.
In most cases, epinephrine is the key treatment that can save a patient's life. It is normally injected. Diphenhydramine (Benadryl) and other H1 type antihistamines can reduce the histamine reaction and are available as an injection or an oral pill. The effect is even more powerful when combined with H2-blocker (H2 type antihistamine). Histamines can relieve itching, which is one of the most annoying symptoms.
Corticosteroids are another effective treatment, since they can reduce the immune response and swelling at the same time. Oral treatments based on steroids and antihistamines should be continued for several days after leaving the hospital, as a general precaution.