insect allergy

Insect AllergyProf. Dr. Saad S Al Ani

Senior Pediatric ConsultantHead of Pediatric Department

Khorfakkan hospitalSharjah ,[email protected]

mailto:[email protected]

April 12, 2023 2

HistoryThe first reports of stinging

insect allergy came from the Middle East thousands of years ago.

Even at that time, people understood that a small insect, such as a bee or a wasp, had the potential to cause serious illness or even death.

http://www.theonlineallergist.com

Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

April 12, 2023 3

Introduction

Allergic responses to stinging

1. Localized cutaneous reactions

2. Systemic anaphylaxis


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Cont.

Allergic reactions that are caused by inhalation of airborne particles of insect origin result in:

1. Acute or 2.Chronic respiratory symptoms of

seasonal or perennial: i. Rhinitis ii. Conjunctivitis iii. Asthma


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Etiology

Most reactions to biting and stinging insects, such as those induced by mosquitoes, flies, and fleas, are limited to a primary lesion isolated to the area of the bite and do not represent an allergic response.


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Cont.

Occasionally, insect bites or stings induce pronounced localized reactions or systemic reactions that may be based on:

1. Immediate or 2.

Delayed hypersensitivity reactions.Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

April 12, 2023 7

Cont.

Systemic allergic responses to insects are attributed most typically to immunoglobulin (Ig)E antibody–mediated responses, which are caused:

i. Primarily by stings from venomous insects of the order Hymenoptera

ii. More rarely from ticks, spiders, and kissing bug.


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Cont.

Systemic reactions to stinging insects occur in 0.4-0.8% of children and 3% of adults


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Cont.

Members of the order Hymenoptera include:

i. Apids: * Honeybee *

Bumblebee ii. Vespids * Yellow jacket *

Wasp * Hornet iii. Formicids * Fire ants *

Harvester ants


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Species of Hymenoptera and their geographical distribution.

Freeman TM: Hypersensitivity Hymenoptera stings, N Engl J Med 351:1978–1984, 2004.)


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Cont.

Freeman TM: Hypersensitivity Hymenoptera stings, N Engl J Med 351:1978–1984, 2004.)


April 12, 2023 12

Pathogenesis

Localized skin responses to biting insects are caused primarily by vasoactive or irritant materials derived from insect saliva, and rarely occur from IgE-associated responses


April 12, 2023 13

Cont.

Systemic IgE-mediated allergic reactions to salivary proteins of biting insects such as mosquitoes are reported but uncommon.


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Cont.

IgE antibody–mediated allergic responses to airborne particulate matter carrying insect emanations contribute to:

1. Seasonal 2. Perennial symptoms affecting the

upper and lower airways


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Seasonal allergy

Attributed to exposures to a variety of insects, particularly aquatic insects such as the caddis fly and midge, or lake fly, at a time when larvae pupate and adult flies are airborne


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Perennial allergy

Attributed to sensitization to insects such as cockroaches and ladybugs as well as house dust mite


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Hymenoptera venoms

Contain numerous components with toxic and harmacologic activity and with allergenic potential.

These constituents include: 1.Vasoactive substances such as histamine, acetylcholine, and kinins 2.Enzymes such as phospholipase and hyaluronidase 3.Apamin4. Melittin5. formic acid


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Cont.

The majority of patients who experience systemic reactions after Hymenoptera stings have IgE-mediated sensitivity to antigenic substances in the venom.


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i. Honey bees are only capable of stinging a person once.

Honey Bee

iii. As the honey bee flies away, it become eviscerated and dies.

ii. The honey bee is the only stinging insect that leaves its stinger and venom sac in the skin of its victim, due to the barbed configuration of the stinger.

http://www.theonlineallergist.comInsect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

April 12, 2023 20

Yellow Jacket

i. Wasp-like insects that live in mounds built into the ground

iii. They are commonly found around garbage cans and picnic areas where food and sugary drinks are abundant

ii. They tend to be very aggressive insects, and will often sting without provocation.



April 12, 2023 21

Hornet

Hornets, including yellow and white-faced hornets, build paper- mache type nests in trees and shrubs

Some hornets look very much like yellow jackets and can be difficult to distinguish

These insects may be very aggressive, and a sting may be provoked by a minor disruption in their environment.



April 12, 2023 22

Wasps

Wasps build honey-comb nests under the eaves of a house, or in a tree, shrub or under patio furniture.

They tend to be less aggressive than yellow jackets and hornets, and mostly feed on insects and flower nectar.http://science.howstuffworks.com



April 12, 2023 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

23

Bumblebees

Bumblebees rarely sting people because they are non-aggressive and typically mild mannered

They generally will sting only if provoked

They nest in the ground or in piles of grass clippings or wood


April 12, 2023 24

Fire Ant

Fire Ant bites are generally quite painful

The bite of a fire ant characteristically Will form into a white pustule within a day or twoScratching these pustules can lead to local infection and scars

It is not unusual to sustain multiple bites, generally on the feet and hands



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Clinical Manifestations

Insect bites are usually urticarial but may be papular or vesicular

Papular urticaria affecting the lower extremities in children is usually caused by multiple bites

IgE antibody–associated immediate- and late-phase allergic responses to mosquito bites sometimes mimic cellulitis


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Clinical reactions to stinging venomous insectsAre categorized

as:

6.Delayed/Late

1. Local

2. Large local

3. Generalized cutaneous

4. Systemic

5. toxic


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Cont.1.Simple local reactions i. Involve limited

swelling ii. Pain iii. Generally last

<24 hr. 2.Large local reactions i. Develop over hours and days ii. involve swelling of extensive areas (>10 cm) that are contiguous with the sting site iii. May last for days


April 12, 2023 28

Cont.3.Generalized cutaneous

reactions Typically progress within

minutes and include cutaneous symptoms of :

i. Urticaria ii. Angioedema iii. Pruritus beyond the site of the sting 4.Systemic reactions are identical to anaphylaxis from other triggers and may include symptoms of : i. Generalized urticaria ii .Laryngeal edema iii. Bronchospasm iv. HypotensionInsect Allergy Prof. Dr. Saad S Al Ani

Khorfakkan Hospital ,Sharjah ,UAE

April 12, 2023 29

Cont.5. Toxic reactions Stings from a large number of

insects at once may result in toxic reactions of :

i. Fever ii. Malaise iii. Emesis iv. Nausea owing to the chemical properties of the venom in large doses.6.Delayed/Late reactions

i. Serum sickness ii. Nephrotic syndrome iii. Vasculitis iv. Neuritis v. Encephalopathy may occur as delayed/late reactions to stinging insectsInsect Allergy Prof. Dr. Saad S Al Ani


April 12, 2023 30

Inhalant allergy

Caused by insects results in clinical disease similar to that induced by other inhalant allergens such as pollens

Depending on individual sensitivity and exposure, reactions may result in seasonal or perennial rhinitis, conjunctivitis, and asthma


April 12, 2023 31

Diagnosis

Generally evident from: i. History of

exposure ii. Typical

symptoms iii. Physical

findings

The diagnosis of Hymenoptera allergy rests in part on the identification of venom-specific IgE by prick skin testing


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Cont.

The primary reasons to pursue testing are to confirm reactivity when: i. Venom immunotherapy (VIT) is being considered ii. It is clinically necessary to confirm venom hypersensitivity as a cause of a reaction


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Cont.Venoms of five Hymenoptera (

1.Honeybee 2.Yellow jacket 3. Yellow hornet 4. White-faced hornet 5. Wasp) as well as the jack jumper ant and whole-body extract of fire ant are available for skin testing

Skin tests are usually accurate within 1 wk of a sting reaction, but occasionally a refractory period is observed that warrants retesting after 4-6 wk if the initial results are negativeInsect Allergy Prof. Dr. Saad S Al Ani


April 12, 2023 34

The diagnosis of inhalant insect allergyMay be evident from a history of typical symptoms induced seasonally in specific geographic regionsSkin prick or in vitro immunoassay tests for specific IgE to the insect are used to confirm inhalant insect allergy


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Treatment

i. Cold compressesii. Topical medications to relieve itchingiii. occasionally the use of a. systemic antihistamine b. oral analgesic are appropriateStingers should be removed promptly by scraping, with caution not to squeeze the venom sac because doing so could inject more venom

For local cutaneous reactions


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Cont.

Sting sites rarely become infected, possibly owing to the antibacterial actions of venom constituentsVesicles left by fire ant stings that are scratched open should be cleansed to prevent secondary infection


April 12, 2023 37

Cont.

Therapies may include: i. Oxygen ii. Epinephrine iii. Intravenous saline iv. Steroids v. Antihistamines

Anaphylactic reactions


April 12, 2023 38

Venom Immunotherapy(VIT)

Hymenoptera VIT is highly effective (95-97%) in decreasing the risk for severe anaphylaxis. The selection of patients for VIT depends on several factors


April 12, 2023 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

39

Indications for venom immunotherapy against winged

Hymenoptera SYMPTOMS AGE SKIN TEST/IN VITRO

TEST

RISK OF SYSTEMIC

REACTION IF UNTREATED

(%)*

VIT RECOMMENDE

D

Large local reaction Any Usually not indicated 4-10 Usually not

indicated

Generalized

cutaneous reaction

≤16 yr Usually not indicated 9-10 Usually not indicated

≥17 yrPositive result 20 Yes

Negative result — No

Systemic reaction

Any

Positive result Child: 40Adult: 60-70

Yes

Negative result — Usually no

*Risks generally decrease after 10 yr

http://www.expertconsultbook.com/expertconsult/b/linkTo?type=bookPage&isbn=978-1-4377-0755-7&eid=4-u1.0-B978-1-4377-0755-7..00140-8--tn0010&appID=NGE

April 12, 2023 40

Prevention Avoidance of stings and bites is essential

To reduce the risk of stings, sensitized individuals should: i. Avoid attractants such as perfumes and bright-colored clothing outdoors ii. Wear gloves when gardening iii. Wear long pants and shoes with socks when walking in the grass or through fields


April 12, 2023 41

Cont.

Typical insect repellents do not guard against Hymenoptera. Nests of these insects should be removed if they are close to the home


April 12, 2023 42

Cont.

Individuals who have had generalized cutaneous or systemic reactions to Hymenoptera stings should have immediate access to self- injectable epinephrineThe individual at risk for anaphylaxis from an insect sting should also wear an identification bracelet indicating the allergyInsect Allergy Prof. Dr. Saad S Al Ani


April 12, 2023 43

Cont.

Avoidance of the insect is the preferred management of inhalant allergyImmunotherapy is occasionally undertaken in such cases, but beneficial results have not been thoroughly documented.


April 12, 2023 44

References


1. http://www.acaai.org/allergist/allergies/types/insect-sting-allergies

2. http://www.theonlineallergist.com3. Freeman TM: Hypersensitivity

Hymenoptera stings, N Engl J Med 351:1978–1984, 2004.)

4. http://www.webmd.com/allergies/guide/insect-stings

5. http://www.aaaai.org/conditions-and-treatments/library/allergy-library/stinging-insect-allergy

6. http://science.howstuffworks.com7. Scott H. Sicherer,Donald Y.M. Leung.

Insect Allergy.(In) Robert M. Kliegman, MD, and Richard E. Behrman, MD. Nelson Textbook of Pediatrics - Chapter 140

http://www.acaai.org/allergist/allergies/types/insect-sting-allergies




http://www.theonlineallergist.com/

http://www.theonlineallergist.com/

http://www.webmd.com/allergies/guide/insect-stings




http://www.aaaai.org/conditions-and-treatments/library/allergy-library/stinging-insect-allergy





insect allergy

Health & Medicine

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insect bites

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