What is Insect Bites?
The phrase “bug bite” is often used to refer to bites or stings from creatures in the Arthropoda group. Arthropoda is the biggest category in the animal kingdom, making up about 80% of all animals. It includes creatures with an external skeleton, jointed legs, and a body broken down into specialized sections.
There are four types of arthropods that can be harmful to humans: Chilopoda, Diplopoda, Insecta, and Arachnida. Among these, insects, which make up more than half of all living organisms, and arachnids (like spiders and scorpions) are the most likely to affect humans.
Bites or stings from these arthropods can cause red and swollen skin eruptions, and sometimes other skin problems like small bumps and hives. In some cases, if the bug injects a harmful poison, it can lead to serious full-body reactions. These might include problems with body’s automatic functions (like heart rate and digestion), brain and nerve issues, and organ failure. Some people might have a severe allergy-like reaction, or anaphylaxis, that happens quickly and can be deadly, mostly because of swelling in deep layers of skin or collapse of the circulation system. If this happens, it’s important to recognize the symptoms and treat quickly with a medication called epinephrine.
On top of these direct effects, arthropod bites can also spread many bacterial, viral, and protozoal diseases, which is one of their biggest impacts on human health.
What Causes Insect Bites?
Insects, arachnids, and other small creatures can cause harm to humans through their bites and stings. Some of these creatures can inject venom when they bite or sting, while others lead to injury or local inflammation due to the body’s reaction to their saliva. Creatures like bees, wasps, hornets, fire ants, and scorpions have stingers. Bites or stings from these organisms can potentially allow bacteria to enter the body, leading to an infection.
Here is a list of some creatures that can be harmful to humans:
– Centipedes: They can cause two painful marks accompanied by swelling and redness when they bite. Cleaning the affected area and applying ice can relieve some of the pain.
– Millipedes: These creatures can release a toxic liquid from their bodies that can cause a burning sensation, redness, and even blisters. The area must be cleaned immediately with soapy water to reduce the effect of the toxin.
– Various insects like bees, wasps, hornets, fire ants, mosquitoes, bedbugs, fleas, beetles, caterpillars, moths, and kissing bugs: Some of these insects cause diseases when they come in contact with their protective hairs or spines. Bedbugs are notorious for their bites which can cause small bumps, usually without a surrounding reaction. Another harmful insect, the Kissing bug, can transmit the parasite causing Chagas disease (a disease affecting the heart and digestive system).
– Lice: These small insects that live in human hair can cause itching. There are three types of lice that feed on humans: the head louse, the body louse, and the crab louse. While head and crab lice are not associated with disease transmission, body lice can transmit diseases like typhus.
– Mosquitoes: Mosquito bites often result in itchiness and the presence of skin rashes. Mosquitoes can also transmit several serious diseases including malaria, Zika virus, and dengue fever.
– Scorpions & Spiders: Scorpions and certain types of spiders, like the Black Widow and Brown Recluse, inject venom that can cause pain, and in rare cases, more serious reactions.
Arachnids also include ticks and mites. Ticks can cut a hole in the skin and inject substances that prevent clotting while they feed. Some ticks can transmit diseases like Lyme disease and Rocky Mountain spotted fever. Mites, on the other hand, can cause conditions like scabies when they burrow into the skin.
While a lot of these creatures and their bites are harmless and result in minor symptoms, some of them can cause serious injuries or spread diseases. Cleaning the affected area thoroughly, applying ice and taking pain relievers can often help with the symptoms. However, it is always important to seek medical attention if any severe reaction or complications occur.
Risk Factors and Frequency for Insect Bites
In the United States, we don’t know the exact number of arthropod (insects and bugs) bites and stings because most of them cause only minor symptoms and people don’t always report it. However, the American Association of Poison Control Centers reported 28,087 cases of contact with arthropods in 2015. It’s important to note that these numbers are likely much lower than the actual number of encounters because many incidents go unreported.
Signs and Symptoms of Insect Bites
People who get bitten or stung by bugs often don’t notice it at first and may not show any symptoms. This makes it important for doctors to ask about things like the person’s job, their hobbies, their travels, and any contact with animals or others with similar symptoms. Sudden pain or itching can be a sign of a bite or sting, especially if the patient saw the bug that bit them.
People showing signs of difficulty breathing or abnormal vital signs should immediately be checked for breathing and heart problems. Anaphylaxis, a serious allergic reaction, can cause symptoms like hives, swelling, fast heart rate, trouble breathing, low blood pressure, and wheezing.
If there’s no sign of severe venom toxicity or anaphylaxis, the doctor should thoroughly examine the affected area.
Bug bites and stings usually show up as red bumps which can be swollen. They might be isolated, grouped, or widespread, depending on the bug. The spot usually itches, and other signs, such as local redness, welts, and hives, are often present. Intense itching can lead to scratched skin and possible secondary infections. The doctor should check for bugs like ticks, lice (head, body, and pubic), myiasis (infestation of fly larvae), or scabies. Sometimes, a bee’s stinger might be left behind and should be removed.
Doctors should also check for signs of diseases carried by insects, as symptoms might not appear for weeks, months, or even years after the bite.
Testing for Insect Bites
If you’re bitten or stung by an insect and only have a minor reaction, there’s no need for medical tests like bloodwork or imaging. But if the bite or sting is from a poisonous insect, causes a secondary infection, or there’s a chance it could lead to a disease carried by insects, more testing might be necessary.
An extremely severe allergic reaction, also known as anaphylaxis, needs immediate treatment with a medication called epinephrine. This condition is diagnosed based on its symptoms and must be treated instantly to prevent serious complications or death.
Very serious insect venom reactions can affect multiple organs in your body. In these cases, your doctor might need to order several tests. These tests can include a complete blood count, basic metabolic panel, liver function tests, coagulation tests, creatine kinase tests, and urinalysis. An EKG, a medical test that measures the electrical activity of the heartbeat, should also be done if your doctor suspects Lyme disease, or if there are problems with your heart’s rhythm. Depending on your symptoms, your doctor might also want to test your blood for diseases like malaria or Chagas disease. Some diseases are more likely to be caused by certain insects. These include:
- Tick-borne diseases such as Lyme disease, Rocky Mountain spotted fever, relapsing fever, anaplasmosis, babesiosis, and tularemia
- Diseases from flies like tularemia, leishmaniasis, African trypanosomiasis, bartonellosis, and loiasis
- Flea-borne diseases such as the plague, tularemia, and murine typhus
- Chigger mites: scrub typhus (almost exclusively in Asia, and not in the US)
- Body Lice: epidemic typhus, relapsing fever
- Kissing bugs: Chagas disease
- Mosquito-borne diseases such as malaria, yellow fever, dengue fever, West Nile virus, equine encephalitis, chikungunya, and Zika virus
Treatment Options for Insect Bites
Most bug bites and stings can be handled at home with easy-to-follow care instructions. These include cleaning the area with soap and water, making sure your tetanus shots are up-to-date if necessary, applying an ice pack, raising the area if it’s swollen, and managing pain with over-the-counter pain relievers like acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs). For itching, which is a common side effect of bites and stings, you can use calamine lotion or a mild topical corticosteroid. If the itching is intense, a short course of oral corticosteroids and antihistamines, which reduce allergic reactions, can often help. If the bite or sting has led to a secondary infection, the treatment should start with the right antibiotics.
If someone experiences a severe allergic reaction to a bite or sting, known as anaphylaxis, it’s crucial to treat it immediately with a shot of epinephrine, which can be repeated every five to fifteen minutes. Additional treatments like corticosteroids, albuterol (used for breathing difficulties), and antihistamines can be helpful but should never delay giving the epinephrine shot.
An anti-venom is available for some venomous bites and stings, but it should be given only after talking to a poison control center, which is available 24/7 at 1-800-222-1222. Additionally, it’s important to check for diseases spread by bugs and start the right antimicrobial treatment if needed.
The best way to avoid the problems caused by bug bites and stings is to prevent them from happening in the first place. Prevention is especially important to prevent severe, and sometimes life-threatening, diseases spread by bugs.
Many prevention methods focus on avoiding mosquito and tick bites as they spread the majority of diseases to humans. The foundation of prevention involves using effective insect repellents that can dramatically reduce the chances of mosquito and tick bites, although they won’t work on other bugs like bees, spiders, fleas, ants, scorpions, and lice. DEET, which is recognized globally as the gold standard bug repellent, is very effective against a wide range of bugs. It’s considered the first choice of repellent, particularly in areas with a lot of mosquitoes. A concentration of 20 to 50% DEET is recommended and can offer several hours of protection from mosquitoes and ticks.
There are also alternatives to DEET like picaridin and PMD – a component of lemon eucalyptus extract. However, these may require more frequent applications to stay effective. Wearing suitable clothing like light-colored pants, long-sleeved shirts, and hats is another good way to avoid insect bites. Using permethrin, a synthetic insect repellent, can enhance the bug repelling property of your clothes. Never apply it directly on the skin, but it can be applied to items like sleeping bags and bed nets. Using mosquito nets, especially those treated with permethin, can be highly effective in preventing bites and stings, making them a recommended item for travelers visiting areas with a high risk of bug-related diseases.
Removing ticks within 24 hours from when they attach may also lower the risk of diseases spread by ticks. So, it’s advisable to check your body regularly for ticks if you’re visiting an area prone to ticks.
What else can Insect Bites be?
: When a person has symptoms that could be from an insect bite or sting, doctors have to consider many different possible causes. These include:
- Contact dermatitis (skin irritation from touching something)
- Drug eruption (skin reaction to a medication)
- Mastocytosis (a build-up of mast cells in the skin and organs)
- Dermatitis herpetiformis (a long-term skin condition causing itching)
- Blistering skin disorders
- Ringworm (a fungal infection creating a circular rash)
- Eczema (dry, red skin that can itch)
- Vasculitis (inflammation of blood vessels)
- Pityriasis (a type of skin rash)
- Erythema multiforme (an allergic reaction causing a skin rash)
- Viral diseases that cause skin rashes
- Cellulitis (a bacterial skin infection)
- Impetigo (a highly contagious bacterial skin infection)
- Folliculitis (inflammation of hair follicles)
- Erysipelas (bacterial skin infection)
- Necrotizing fasciitis (a severe bacterial infection of the tissue under the skin)
For patients who have a skin ulcer that might be from a brown recluse spider bite, doctors also look for signs of other conditions such as:
- Pyoderma gangrenosum (a rare skin condition causing painful sores)
- Staph or strep skin infections
- Diabetic ulcers
- Necrotizing fasciitis
- Fungal infections
- Leishmaniasis (a parasitic disease)
- Sporotrichosis (a rare infection caused by fungus)
Moreover, the symptoms of a black widow spider bite may resemble those of severe abdominal issues, so this needs to be considered as well during diagnosis.
What to expect with Insect Bites
Most bites and stings from arthropods, which are invertebrates, like insects and spiders, typically result in simple skin reactions, and severe complications are not common. However, there are a few instances where the bite or sting could potentially be fatal within the first hour, typically due to an extreme allergic reaction, also known as anaphylactic shock. Prompt administration of a medication called epinephrine (commonly known as an EpiPen), can significantly decrease the risk of this severe reaction becoming fatal.
The most significant concern associated with arthropod bites, in terms of health, is the possible transmission of infectious diseases. The outcomes after acquiring an arthropod-borne infectious disease vary, depending on how the specific organism transmitted through the bite or sting affects the body.
Generally speaking, the prognosis, or anticipated outcome, following a bite leading to envenomation (meaning venom has been injected into the body), is very good. Treatment usually involves managing the signs and symptoms and providing supportive care. While deaths are rare, children, older adults, and those with pre-existing serious heart conditions may have a slightly higher risk.
