insect allergy symptomsand Anaphylaxis due to Hymenoptera stings is one of the most severe consequences of IgE-mediated hypersensitivity reactions. Although allergic reactions to Hymenoptera stings are often considered as a general model for the underlying principles of allergic disease, diagnostic tests are still hampered by a lack of specificity and venom immunotherapy by severe side effects and incomplete protection. In recent years, the knowledge about the molecular composition of Hymenoptera venoms has significantly increased and more and more recombination venom allergens with advanced characteristics have become available for diagnostic measurement of specific IgE in venom-allergic patients.
These recombination venom allergens offer several promising possibilities for an improved diagnostic algorithm. Reviewed here are the current status, recent developments, and future perspectives of molecular diagnostics of venom allergy. Already to date, it is foreseeable that component-resolution already has now or will in the future have the potential to discriminate between clinically significant and irrelevant sensitization, to increase the specificity and sensitivity of diagnostics, to monitor immunotherapeutic intervention, and to contribute to the understanding of the immunological mechanisms elicited by insect venoms.
Insect allergy symptoms
Allergy to the venom of Hymenoptera species is a classical IgE-mediated allergic disease caused by the cross-linking of receptor-bound IgE antibodies on the surface of mast cells and basophils. Hymenoptera venom allergy is one of the most severe hypersensitivity reactions with regard to the high risk of anaphylactic reactions with potentially fatal outcome.
Although venom allergy is one of the most frequent triggers of anaphylactic reactions in adults the true number of fatalities may be underestimated since a study reports the presence of venom-specific IgE in 23 % of post-mortem serum samples taken from subjects, who had died outdoors suddenly and inexplicably between May and November .
Approximately 9.2 to 28.7 % of the adult population shows a sensitization to Hymenoptera venom and the prevalence of systemic sting reactions among adults ranges between 0.3 and 7.5 % . A preferential association was observed between Hymenoptera venom allergy and mastocytosis since 20 to 39 % of patients with mastocytosis suffer from Hymenoptera venom allergy. In addition to the higher prevalence of systemic reactions to Hymenoptera venom in adult patients with mast cell disorders, there are several reports which suggest that these patients are at risk for more severe reactions following stings
Globally, all allergy-eliciting Hymenoptera belong to the suborder Apocrita which consists of the superfamiliesApoidea (Apinae and Bombinae subfamilies) and Vespoidea (Vespinae, Polistinae, Formicinae, andMyrmicinae subfamilies). In western and central Europe, the predominant elicitors of venom allergy are stings of honeybees (Apis mellifera) and yellow jackets (Vespula vulgaris). In southern Europe and the United States (US), additionally allergic reactions to paper wasps (Polistinae) are common In Europe, allergic reactions to ants are rare while they are of great importance in the US (especially Solenopsis invicta) and Australia (especially Myrmecia pilosula)
For patients with anaphylactic reactions to Hymenoptera venom, the only causative treatment which is effective in reducing the risk of subsequent systemic reactions is venom immunotherapy (VIT). Particularly in Hymenoptera, venom-allergic patients specific immunotherapy is very effective in inducing tolerance with a protection rate ranging from 75 to 98 % Prerequisite for the initiation of VIT should be the verification of an IgE-mediated reaction against the culprit venom. An unnecessary treatment with more than one or even with the wrong venom can lead to de novo sensitizations increased risk of side effects and missing or limited protection to further stings and moreover, drastically increases the treatment costs.
The diagnosis of Hymenoptera venom allergy comprises the past medical history of a systemic sting reaction, a positive skin test response, and the detection of venom-specific IgE antibodies. Especially when the patient was not able to definitely identify the culprit insect, in clinical practice, the correct diagnosis is not always straightforward due to inherent problems and limitations of both tests. On the one hand, there are patients with a convincing history of anaphylaxis but negative diagnostic tests and, on the other hand, up to 50 % of patients show positive tests with more than one venom. Moreover, to date, no molecular tools are available which allow the prediction of the success of venom immunotherapy.
Several limitations of diagnostic tests are based on the use of whole venom preparations for diagnosis. Venom preparations just like many other allergen extracts such as pollen or mite extracts often might show a highly variant allergen composition, which is essentially based on natural variability of the source material and additionally increased by different processing modalities or degradation of labile allergens, and in some cases, underrepresentation of particular allergens of high relevance. Hence, the reliability of diagnostic approaches is hampered by using venom extracts and the variant composition and low abundance of particular allergens even might affect therapeutic efficacy.
In recent years, significant progress has been made in the identification of novel Hymenoptera venom allergens, the detailed characterization of established allergens, and the development of suitable strategies for the recombinant production of venom allergens.
Stinging insect allergy generally involves an allergy to the sting of what we term the Hymenoptera which are the stinging insects generally includes hornets, wasps, bees, even fire ants can cause a similar type of allergy.
Symptoms of Insect Sting Allergies
And certain individuals will be allergic to the venom from the stinging insect whereas other individuals will not.
In a nonallergic individual, you can still get redness, pain, local swelling.
That’s pretty common with any stinging insect, if it starts spreading in a limb beyond the elbow, for instance, beyond the wrist all the way down the hand or you start getting symptoms elsewhere like hives on the leg when you are stung in the arm, swelling which can be especially relevant in the face, tongue, throat that can cause trouble breathing or even a full blown allergic reaction where multiple systems get involved and some individuals will even feel their blood pressure drop, feel like they’re going to faint.
Stinging insects can be very serious in terms of allergy and can cause even fatal reactions.
How to Diagnose Insect Sting Allergies
We will start with a clinical history which can give us some clues.
And often time’s patients will know exactly what they were stung by or that they were stung right next to a wasps’ nest so that we can guess that it was the wasp.
But, we’ll generally do a full panel of testing, both with skin prick testing, where we put an extract to every stinging insect that we know.
And then we will gradually increase the concentration of the prick and move into an intradermal tests where it is injected under the skin and then we’ll separately also do specific IGE testing which is looking for the specific IGE which is the allergic antibody against each of these stinging insects.
Treatment Options for Insect Sting Allergies
The most important thing for patients who are truly allergic to insect stings is to carry an epinephrine auto injector and to know how to use it.
So, making sure that they themselves know how to use it other loved ones who will be around them at a time when they might get stung also knows how to use them.
In addition, we advise avoidance of some areas where we know that stinging insects tend to hide.
So, for instance, a soda can at a picnic.
There might be a stinging insect in there and drinking that stinging insect could cause you problems in terms of an allergic reaction.
In addition, there actually are allergy shots against stinging insects so that is something that a lot of people are not aware of, but certainly in patients who have had severe insect sting reactions, some of which have been life threatening, or people who work in areas such as golf courses or as bee keepers where they really can’t practice avoidance, then we’ll try to make them tolerant of the stinging insect venom by doing allergy shots.
Insect Allergy symtoms and Stings allergy Reactions
Avoiding insect stings may not always be possible. But it’s important to know how to respond if your child has an allergic reaction from an insect sting. This may give you more peace of mind if there is an emergency.
Insect stings that most commonly cause allergic reactions
Insects that are members of the Hymenoptera family most commonly cause allergic reactions. These include:
- Honey bees
- Yellow jackets
- Fire ants
What are the symptoms of an allergic reaction to an insect sting?
Most children who are stung by an insect have a local reaction at the sting site. The reaction is brief, with localized redness and swelling followed by pain and itching. Generally, the reaction lasts only a few hours. But some may last longer.
For other children, their immune system reacts abnormally. It causes an allergic reaction that can spread to other parts of the body. Sometimes this reaction can be life-threatening.
This severe reaction is a medical emergency that can happen very quickly. It is called anaphylaxis or anaphylactic shock. It can include severe symptoms such as:
- Itching and hives over most of the body
- Swelling of the throat and tongue
- Trouble breathing and chest tightness
- Stomach cramps, nausea, or diarrhea
- Quick drop in blood pressure
- Loss of consciousness
- Hoarse voice or swelling of the tongue
Call 911. Immediate medical care is needed. If your child has an epinephrine auto-injector pen, use it as directed.
Can insect stings be prevented?
Helping your child avoid insect stings is the best preventive measure. Try the following:
- Teach your child not to disturb insect nests and mounds.
- When outdoors, make sure children who have severe reactions wear socks, shoes, long pants, and long-sleeved shirts.
- When outdoors, make sure your child is careful if eating or drinking uncovered foods or drinks, which can attract insects.
- Keep your child from going barefoot. He or she should wear closed-toe shoes when walking in grassy areas.
- When playing outdoors, make sure you and your child watch for insect nests in trees, shrubs, and flower beds. Other areas in which to be careful include swimming pools, woodpiles, under eaves of houses, and trash containers.
- Before letting children play in an area, check for nests. These can be found in older tree stumps, holes in the ground, and rotting wood. Car tires used in playgrounds can also contain nests.
- If your child is allergic to insect bites, don’t let him or her play outside alone when stinging insects are active. Even a dead insect can sting if a child step on its stinger to picks it up.
- Teach children to walk away slowly from insects. Don’t teach them to swat at insects or run away. This can trigger an attack.
- A child with an insect sting allergy should wear a medical alert bracelet or necklace.
Treatment for insect stings
Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.
If your child has had a serious reaction to an insect sting, make an appointment with an allergist. An allergist can do skin testing, diagnose the allergy, and figure out the best form of treatment. In some cases, insect venom allergy shots (immunotherapy) are very effective.
Here’s how to provide immediate treatment for an allergic reaction that is not life-threatening:
- Stay calm. Your composure will help your child remain calm too.
- When possible, remove the stinger right away using a pair of tweezers. Try not to squeeze the stinger. That could force the venom into the body. But speedy removal is the most important step.
- Call your child’s healthcare provider if he or she gets several stings. Or if hives develop in a part of the body away from the sting itself.
- Raise the affected arm or leg. This will help reduce swelling.
- Apply ice or a cold compress to reduce swelling and pain. To make an ice pack, put ice cubes in a plastic bag that seals at the top. Wrap the bag in a clean, thin towel or cloth. Nevert put ice or an ice pack directly on the skin.
- Clean the area with soap and water.
- Apply a topical steroid cream to the sting site to ease itching.
- Give your child a dose of an antihistamine taken by mouth (such as diphenhydramine) to ease itching. If your child has a serious health condition or takes prescription medicines, check with the healthcare provider before giving the antihistamine.
- For children with a history of a severe allergic reaction to a sting, always keep an emergency treatment kit nearby. The kit should contain life-saving adrenaline (also known as an epinephrine auto-injector, prescribed by your child’s healthcare provider). Alert your child’s school and have an emergency plan and an emergency kit immediately accessible.
- If your child’s symptoms get worse, call 911 and seek emergency care.