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Hornets are stinging insects that are part of the wasp family. They are one of the thousands of species in the hymenopteran order. This order also includes bees, ants, and other wasps.

Hornets are about an inch in size and have yellow stripes that contrast against dark bodies. They are winged and have antennae, legs, and a stinger.

Hornet stings generally cause mild symptoms, but they can result in allergic reactions or other serious symptoms. Hornet venom contains a histamine that can trigger severe allergic reactions in people.

Most of the time, you can treat hornet stings on your own, but you should seek immediate medical treatment if your symptoms are severe.

Hornets live throughout the United States and the world. You may be most likely to encounter hornets when outside. Their nests can be near dwellings or in nature, such as in decayed trees or shrubs.

Hornets are more prone to sting when they feel threatened. A single hornet can sting once or multiple times, and sometimes hornets swarm and can cause tens or hundreds of stings.

Most hornet stings are mild and will cause minor symptoms. However, you may experience an allergic reaction, infection, or more serious symptoms. Fewer than 10 percent of stings can cause larger reactions near the sting. Stings from bees and wasps result in about 100 deaths in the United States each year.

Common, nonemergency symptoms

Generally, hornet stings will only affect the area where you are stung. These symptoms may last a few hours or up to a day.

Mild symptoms include:

  • a raised, reddish area where the sting occurred
  • warmth near the sting
  • pain near the sting
  • itching
  • bleeding
  • possible hives near the sting

Anaphylaxis and other allergic reactions

An allergic reaction following a hornet sting may lead to more severe symptoms or even anaphylaxis. This is because hornet venom contains histamines that can trigger allergic reactions. Anaphylaxis is a very serious and life threatening condition. It can affect between 1.2 and 3.5 percent of people. Symptoms include:

  • hives beyond the sting site
  • swelling of the skin or in the throat
  • flushed skin
  • coughing
  • breathing difficulty
  • chest tightness
  • wheezing
  • nausea
  • vomiting
  • sweating
  • shock

Anaphylaxis can occur quickly and can be fatal in a short amount of time. Make sure you seek immediate medical care if you experience these symptoms.

Severe and lingering symptoms

You may experience symptoms that are neither mild nor the result of anaphylaxis. Symptoms that last longer than a day, as well as those that get worse over time, should be monitored. Additionally, stings near your nasal passages, mouth, and throat could lead to serious symptoms.

One case study examined the symptoms of a middle-aged man stung only one time by a hornet. He developed swelling along the entire right side of his body and blisters on his arms and legs. He needed to be treated in the hospital with corticosteroids and antihistamines for a week.

Hornets may sting multiple times, or you may encounter a swarm of hornets. Multiple hornet stings can cause more symptoms and may be life threatening. For example, in Sri Lanka, the hornet Vespa affinis can swarm humans, and stings can result in heart attacks, organ failure, or other health conditions.

Type of insectSymptomsWhere you might encounter itPainOther notes
HornetPain

Skin redness

Swelling around the sting
In a nest near a building

Under a roof

In a tree or shrub

In rotting tree stumps

Around fallen logs
Pain is present and may occur for several hoursHornets retain their stingers and can sting multiple times

Can be aggressive

Anaphylaxis sometimes occurs
HoneybeesPain

Skin redness

Swelling around the sting
Near a beehive

In flower patches, meadows, and other grassy, natural areas
Pain is present and may occur for several hoursStingers dislodge in the skin after one sting and can continue to release venom

Can remove stingers with the swipe of a credit card or butter knife

Anaphylaxis can occur
Other wasps (yellow jacket, paper wasp, wingless wasps)Pain

Skin redness

Swelling around the sting
While eating outdoors

Around buildings and other structures where they build nests
Pain is present and may occur for several hoursWasps retain their stingers and can sting multiple times

Some wasps are solitary, but yellow jackets and hornets can be more aggressive

Anaphylaxis can occur
Fire antsBites may be in a circular pattern

Bites turn into pustules that can last a week
Prevalent in the southern United States

Nests appear to be mounds of dirt
Burning sensation that can last for several hoursCan sting multiple times

Often leads to infection

Rarely causes anaphylaxis
Mosquitoes (bite, not sting)Wheal on the skin that is raised, light pink, or red

Itching
Areas with standing water

Grasses

Bushes
MildOnly rarely causes disease

Hornets are around an inch long, but they may be slightly shorter or longer. They are multicolored, and many have yellow or white stripes that contrast against their brownish red and black bodies. Their heads are lighter in color and they have very large, dark eyes.

Hornets have antennae, two wings, and six legs. They have a stinger at the end of their body that is connected to a gland that contains venom. Their stingers are smooth, so they won’t fall out after stinging. This is unlike bees that have barbs on their stingers and lose them upon stinging. Only female hornets can sting.

Mild cases

In most cases, you can treat a hornet sting on your own:

  1. Make sure to clean the affected area with soap and water.
  2. Apply a cold compress to the site of the sting to dull pain and reduce swelling.
  3. If stung on your arm or leg, elevate it to reduce swelling.
  4. Take or apply over-the-counter medications like antihistamines or corticoid steroids to reduce symptoms near the sting.
  5. Consider taking acetaminophen to manage pain if needed.

Hornets don’t leave their stingers behind, so you won’t need to remove it like you would if stung by a bee.

Some home remedies may help insect stings.

Prolonged or severe symptoms

Symptoms that don’t go away after a few hours or days should be treated a bit more aggressively. You may need a prescription medication like a steroid to reduce inflammation.

Allergic reactions

Hornet stings that trigger an allergic reaction or anaphylaxis require immediate medical attention. If you know you’re allergic to stings and carry an epinephrine pen (Epi-Pen), use it immediately. Administer this pen by injecting it into the thigh.

Anaphylaxis may also require intubation and other medical treatment like steroids and IV fluids. Call for emergency help if someone experiences anaphylaxis following a hornet sting. You’ll need to treat it within minutes, if possible.

Preventive treatment

You should protect yourself against hornet stings by remaining calm if you encounter them, covering yourself in protective clothing when outdoors, and using insect repellent. Additionally, bright-colored clothing may attract hornets more than dark- or neutral-colored clothes.

Symptoms that linger beyond a day or so or become more severe require a doctor’s consultation. These may be signs of an allergic reaction or an infection.

Anaphylaxis symptoms like trouble breathing, fainting, and severe swelling require immediate medical care. If you experience any of these, call for emergency help.

You may experience a hornet sting when outside. A single hornet sting may only cause minor symptoms around the sting for a short amount of time. However, hornets may sting multiple times or in groups. Or, you may be allergic to the hornet’s venom, and this requires more medical care.

Seek immediate medical attention if you experience trouble breathing, loss of consciousness, or other severe symptoms.