Wasp Sting

What are wasps?

A wasp is a member of a group of insects in the order Hymenoptera, suborder Apocrita, and some of which are stinging.  Wasps have a slender, smooth body and legs with relatively few hairs. Wasps have a narrow waist, which attaches the abdomen to the thorax.  Wasps have biting mouthparts and antennae with 12 or 13 segments and are normally winged.

In stinging species of wasp, only the females are equipped with a formidable sting, which involves the use of a modified egg-laying structure for piercing and venom-producing glands.  Adult wasps generally feed on nectar and some species of wasps feed on the secretions produced by the larvae.

Wasps are subdivided into two groups, namely the solitary wasps, which live alone, and social wasps, which live in colonies.  Out of numerous species of wasps, the vast majority are solitary wasps. The social wasps are generally more aggressive compared to the solitary wasps and include the hornets and yellow jackets.

Wasps: Interesting revelations

Solitary wasps generally build isolated nests and provision them with paralyzed insects or spiders. The female wasp deposits an egg in each cell of the nest, and the wasp larva hatching from the egg feeds upon the food with which its cell has been provisioned. The vast majority of the solitary wasps nest in the ground, digging tunnels in the soil, whereas thread-waisted wasps build their nest in wood, pithy plant stems, or in nests made of mud.  Spider wasps build nests in rotten wood or in rock crevices.  The potter, or mason, wasps build nests of mud, which are sometimes vase-like or jug-like and may be found attached to twigs or other objects.

Social wasps are the best-known species of wasps. Social wasps have a caste system consisting of one or several queens, a few drones, which include males and sterile females called as workers. The queen is a fertilized female and begins the colony in the spring by building a small nest and starts laying eggs that hatch and become workers. The workers enlarge the paper-like nest, which is composed of chewed dry plant material, usually wood, that has been mixed with saliva and regurgitated. The nest of these wasps are generally seen in the soil, trees, hanging from leaves, as well as eaves of buildings.

The most familiar social wasps in northern temperate are large and aggressive and are equipped with formidable stings.  Some species are called yellow jackets because of the black and yellow bands on their abdomen. Other species are called hornets, which are mostly black, with yellowish markings on the face, thorax, and the tip of the abdomen.  The Asian giant hornet is the largest known hornet in the world and the workers grow to nearly 4 cm (1.6 inches) in body length and queen typically exceeding that size.

Why do they sting?

The main reason wasps sting humans is because they feel threatened.  A wasp stings a human merely to defend itself whereas in the wild a wasp stings to catch their prey.

There are two main reasons people might get stung by a wasp.

• To protect itself against any threat:  When a wasp female gets a feeling that her home is under attack or gets threatened by either human or other beings, she will try to protect the nest acting quickly by trying to minimize the threat or wade off the threat by stinging the opponent.
• When the wasp gets agitated:  Wasps get annoyed or feel threatened by the constant waving of arms and newspapers while trying to get rid of a wasp, which can be the main reason for the wasp to sting a human.

Why does a wasp sting hurt?

Wasp stinger consists of a large amount of venom in it, which is why they are so painful.  Reaction to wasp sting generally varies from person to person. Having one type of reaction does not mean we will always have the same reaction every time when we are stung. Wasp venom induces a toxic reaction at the site of the sting.  

Large local reactions are due to allergy and occur in up to 25% of the population and as many as 3.5% develop IgE-mediated, potentially life-threatening anaphylaxis.  The acute symptoms of a wasp sting are treated symptomatically. Any person who has a reaction that also affects other organs of the body including the large local reaction due to insect allergy must act quickly and take medical treatment, as well as follow measures to avoid further allergen reaction by making sure they can treat themselves when stung by a wasp again.  

Most patients suffering from systemic anaphylactic reactions due to the wasp sting may need a specific immunotherapy.

Wasp venom is a staged attack against the nervous system on a cellular level as discussed below:

The stinger delivers the venom to the victim’s bloodstream.

Peptides and enzymes in the venom break down cell membranes, spilling cellular contents into the bloodstream.  When the cells affected are neurons, which serve the central nervous system, this breach causes the injured cell to send signals back to the brain and we experience these signals in the form of pain.

A substance in the venom called as norepinephrine, stops the flow of blood and this is the main reason why the pain of a wasp sting can last for several minutes until the bloodstream flushes out the venom away.

Hyaluronidase and MCDP (mast cell degranulating peptide) that are present in the wasp venom spreads to other cells of the body causing the area to swell and become red.

A wasp’s venom generally serves two purposes:

• Wasp venom is very powerful such that it can paralyze their prey so that the prey can be transported back to the nest easily.
• Wasp venom is so powerful that it induces pain in a high level to the animals and humans so that they leave the scene immediately.

The Schmidt Pain Index

The Schmidt Pain Index is a pain scale which enables us to find the pain level caused by stings of different insects, including wasps.  Justin O. Schmidt is the founder of Schmidt pain index when he placed himself for experiencing the range of pain caused by different stings from different insects.  Below is a description of experience when suffering from these painful stings as well as the duration. The description is provided for the most common wasp stings:

Yellowjacket

• Schmidt Pain Index: 2.0
• Pain Duration: 10 minutes.
• Description:  Feeling of heat and pain

Paper wasp

• Schmidt Pain Index: 3.0
• Pain Duration: 5 to 10 minutes.
• Description: Burning and chemical reaction.

Tarantula hawk wasp

• Schmidt Pain Index: 4.0
• Pain Duration: 5 minutes.
• Description:  A very aggressive and shocking reaction.  A person may end up screaming when stung by this particular wasp.

What are the symptoms of a wasp sting?

The majority of people are not very allergic to the wasp sting and the initial sensations can include sharp pain or burn at the sting site followed by redness, swelling, and itching as well.

Normal local reactions:  A person is likely to develop a raised welt around the sting site with a tiny white mark visible in the middle of the welt where the stinger punctured the skin. Generally, the pain and swelling recede within several hours of being stung and can be treated at home.

Large local reactions:  Large local reactions are more pronounced symptoms associated with a wasp sting.  Large local reactions occur to people who may be allergic to wasp stings but are not severely allergic to cause life-threatening symptoms, such as anaphylactic shock.  Extreme redness and swelling are experienced by the person stung by a wasp, which can gradually increase for another two or three days with nausea and vomiting accompanying it.  Large local reactions generally subside on their own over the course of a week.  

A doctors consult may be required for a large local reaction, who will prescribe over-the-counter antihistamine medication to reduce the discomfort. Generally, the body’s immune system encrypts the allergic reaction produced during the first sting and creates an antidote in the body’s immune system, so having a large local reaction after a wasp sting one time does not necessarily mean the person will have the same reaction in the future.  A person could have one strong reaction and never show the same symptoms again.

Anaphylaxis from a wasp sting

Anaphylaxis is defined as a complex allergic reaction and requires immediate attention by a medical professional.  The most severe allergic reactions to wasp stings called as anaphylaxis occurs when the body goes into shock in response to the wasp venom.  Most people with severe allergic reactions to wasp venom go into shock very quickly and need to seek immediate emergency care to treat anaphylaxis.

Symptoms include:

• Abnormal enlargement of the face, lips, or throat.
• Red bumps and itching in other parts of the body.
• Respiratory issues including wheezing or gasping.
• Dizziness.
• Hypotension.
• Lightheadedness.
• Loss of consciousness.
• Nausea or vomiting.
• Diarrhea.
• Stomach cramps.
• Weak or racing pulse.

A person having a severe allergic reaction may experience at least some of the above symptoms and not necessarily all of them after a subsequent sting.  According to research people who have gone into anaphylactic shock after one sting is 30 percent to 60 percent more likely to show the same reaction in the future.  

When a person is diagnosed with an anaphylactic reaction to a wasp sting, it is advised by the doctor to carry a wasp sting kit, which contains epinephrine injections (EpiPens) which can be administered by the patient immediately after a wasp sting.  Epinephrine relaxes the muscles and blood vessels, helping the heart and respiration rates return to normal.

Treatment for wasp sting

Mild to moderate reactions:  Mild and moderate reactions to wasp stings can be treated at home.  The following points are to be followed while treating a wasp sting at home:

• Wash the sting area with soap and water to remove as much of the venom as possible.
• An ice pack can be used to subside the swelling and pain.
• Infection preventing measures to be followed.
• Bandage the area.

We can use hydrocortisone cream or calamine lotion if itching or skin irritation becomes bothersome.  Baking soda can give a soothing effect when applied to the sting area. Pain medications such as Ibuprofen is sufficient to relieve the pain.  

Antihistamine drugs are used for treating the itching. Consider getting a tetanus shot within several days of the sting if a booster shot is pending for more than 10 years.  It is recommended to administer EpiPen as soon as symptoms of severe allergic reaction appear.  Treatment for severe allergic reactions to wasp stings includes:

• Additional epinephrine to calm the immune system.
• Cardiopulmonary resuscitation (CPR) to regain the pulse.
• Respiratory therapy for breathing difficulties.

Wasp sting: Important pointers

The main reason wasps sting humans is when they feel threatened and merely to defend itself. The majority of people are not very allergic to the wasp sting and the initial sensations can include sharp pain or burn at the sting site followed by redness, swelling, and itching as well.  The most severe allergic reactions to wasp stings called as anaphylaxis occurs when the body goes into shock in response to the wasp venom.

Most people with severe allergic reactions to wasp venom go into shock very quickly and need to seek immediate emergency care to treat anaphylaxis.  A mild to the moderate reaction can be treated at home and generally subsides within a week. Anaphylaxis to wasp sting requires immediate medical attention and administration of epinephrine. The bottom line is that a wasp stings only when they feel threatened and it is advised to avoid any interaction with a wasp knowingly or unknowingly.

References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334720/
https://www.webmd.com/first-aid/bee-and-wasp-stings-treatment#1
https://emedicine.medscape.com/article/169324-overview
https://www.healthline.com/health/wasp-sting#complications
https://www.medicalnewstoday.com/articles/297999.php