Overview of arthropod allergies Routes of exposure for arthropod allergens and target organ of arthropod allergic diseases Immune response to arthropod allergens Pathogenesis of arthropod allergies Arthropod species involved in allergic diseases Immuno-diagnosis, skin prick tests. Allergen-specific immunotherapy, desensitization Prevention and prophylaxis Impacts of arthropod allergy on individual and community health

1. ARTHROPOD
ALLERGIES
MD Arthropod
D. Ibrahim Abouelasaad

2. Lecture
Headlines:
• Overview of arthropod allergies
• Routes of exposure for arthropod allergens
and target organ of arthropod allergic diseases
• Immune response to arthropod allergens
• Pathogenesis of arthropod allergies
• Arthropod species involved in allergic diseases
• Immuno-diagnosis, skin prick tests. Allergen-
specific immunotherapy, desensitization
• Prevention and prophylaxis
• Impacts of arthropod allergy on individual and
community health

3. Allergen and Antigen
• Allergen and antigen are both foreign substances that can cause certain disorders to
animals, Both these substances, allergen and antigen, are directly associated with
the immune system and its functions.
• Allergens are type of antigens but there is some difference between them in terms of
their nature and the diseases caused by them.
Differences between Allergen and Antigen:
Allergen Antigen
Allergen is a foreign substance that can cause
certain hypersensitivity reactions (IgE-
mediated) when it enters the body.
Antigen is a foreign substance that can trigger
immune system to produce a specific immune
response by the production of antibodies.
Allergens are non-pathogenic agents (dust,
pollen, pet dander or certain
arthropod allergens)
Antigens can be chemical substances (proteins,
glycoproteins) or pathogens (parasites, bacteria
and viruses)
Allergen can lead to certain allergic disorders
like urticaria, dermatitis, edema, asthma, etc.
Antigen can lead to specific diseases like
bacterial and viral diseases, autoimmune
diseases, etc
Thus, all allergens are considered antigenic , but many antigens are not allergenic
Overview

4. Target organ of arthropod allergic diseases:
• Digestive tract contact results in vomiting,
cramping, diarrhea.
• Skin sensitivity usually reddened inflamed area
resulting in itching.
• Airway sensitivity results in sneezing and rhinitis
OR wheezing and asthma.
• Systemic anaphylaxis: Systemic vasodilation and
smooth muscle contraction leading to severe
bronchiole constriction, edema, and shock.
Arthropod Allergic Diseases includes:
• Allergic rhinitis,
• Bronchial asthma,
• Allergic conjunctivitis,
• Allergic dermatitis,
• Allergic gastroenteritis,
• Systemic anaphylaxis, and
• Local immediate hypersensitivity reactions like urticaria.
Arthropod allergens may induce allergy through:
o Inhalation of arthropod allergens (Inhalant allergy, Atopy)
o Direct contact to arthropod allergens, as Caterpillar dermatitis & Dermatitis linearis
o Inoculation of arthropod allergens with;
• Saliva during biting (insect bite allergy), or with
• Venom during stinging (insect venom allergy).
o Ingestion: Digestive tract contact results in vomiting, cramping, diarrhea.

5. Immune response to
arthropod allergens
• The immune response to arthropod
allergens, like most allergic reactions, is
a complex interplay of cellular and
humoral mechanisms. The immune
response to arthropod allergens
explains the mechanism of Arthropod
Induced Allergy.
• Here's a breakdown of the immune
response:

6. • Sensitization Phase:
• When an individual is first exposed to an allergen from an arthropod (e.g., proteins in bee venom
or proteins in mosquito saliva), the immune system recognizes these foreign substances.
• Antigen-presenting cells (APCs) such as dendritic cells capture these allergens and present them
to helper T cells.
• In genetically predisposed individuals, this can stimulate the differentiation of naïve helper T cells
into a subtype called Th2 cells.
• Th2 cells release various cytokines, including IL-4, IL-5, and IL-13, which promote the production
of Immunoglobulin E (IgE) by B cells.
• Production of IgE:
• Under the influence of Th2 cytokines, B cells will switch their immunoglobulin production to IgE
specific to the arthropod allergen.
• This IgE then binds to high-affinity receptors (FcεRI) on the surface of mast cells and basophils,
sensitizing them to the allergen.
• Subsequent Exposure:
• Upon re-exposure to the same allergen, it binds to the IgE on the mast cells and basophils.
• This cross-linking of IgE molecules triggers a signaling cascade within these cells, leading to
degranulation.

7. 4) Degranulation and Mediator Release:
• Mast cells and basophils release preformed mediators like histamine and tryptase.
• They also synthesize and release other mediators such as leukotrienes, prostaglandins, and
cytokines.
• Histamine is particularly responsible for many of the immediate symptoms of allergic reactions,
like itching, swelling (edema), and redness.
• Leukotrienes and prostaglandins can prolong the inflammatory response and cause more tissue
damage.
5) Late Phase Reaction:
• Hours after the immediate allergic response, a "late phase" reaction can occur. This involves the
attraction of other immune cells, such as eosinophils, neutrophils, and Th2 cells, to the site of
the allergen exposure.
• Eosinophils, in particular, can release toxic granules that cause tissue damage and prolong the
inflammatory response.
6) Chronic Allergic Inflammation:
• In situations where there is repeated or chronic exposure to the allergen (as can happen with
house dust mites, which are arthropods), a persistent inflammatory response can occur.
• Over time, this can lead to tissue remodeling and chronic symptoms. For instance, chronic allergic
responses in the lungs can lead to symptoms consistent with asthma.
7) Regulatory Mechanisms:
• The immune system also has regulatory cells, such as regulatory T cells (Tregs), which can
suppress the allergic response.
• In some individuals, a lack of or insufficient regulatory response might contribute to more severe
or persistent allergic reactions.

8. Mechanism of allergy induced
by Arthropod Allergens
• Many species of arthropods are the sources of
potent allergens that sensitize and induce type 1
hypersensitivity reaction in humans.
• Type I reactions (immediate hypersensitivity
reactions) involve IgE–mediated release of
histamine and other mediators from mast cells and
basophils.
• T and B cells play important roles in the
development of the immediate hypersensitivity
reactions. These reactions takes place in two
phases:
• Sensitization phase: At first contact with an
allergen
• Effector phase: In a subsequent exposure to
the same allergen.

9. Sensitization
phase
• Mechanism of sensitization phase in allergic disease:
• Mucosal dendritic cells (DC) capture antigen (allergen), which are transported to neighboring lymph nodes
• Antigen is processed by APC and then presented to naïve T cell
• In the presence of IL-4, the naïve Tcll develops into antigen specific TH2 cell
• Activated allergen-specific Th2 cells further produce IL-4 and IL-13 which favors B cell isotype class switching to
specific IgE cells,
• The B cell can then differentiate into plasma cell, which can produce more antigen specific IgE.
• The IgE can then bind to the surface of mast cells and basophils via high affinity IgE receptor leading to
sensitization.
• During this phase, a memory pool of allergen-specific B cells and allergen-specific Th2 cells are generated

10. Mechanism of effector phase in allergic disease.
• Immediate phase (occurs in minutes): During the effector phase, subsequent encounters to a
previously sensitized allergen leads to IgE cross-linking on and activation of basophils and
mast cells. Basophil and mast cell degranulation leads to the release of anaphylactogenic
mediators such as histamine, proteases, prostaglandins, leukotrienes, and cytokines which
are the cause of the immediate symptoms and acute inflammation.
• Late phase (occurs in hours ): As these cytokines accumulate, allergen-specific Th2 cells are
activated and produce IL-4, IL-5, and IL-13 among other cytokines, which maintain allergen-
specific IgE levels, eosinophilia, mucus production, and recruitment of inflammatory cells to
inflamed tissues leading to tissue damage
Effector
Phase

11. Arthropod
Species
Involved in
Allergic
Diseases

12. Arthropod species causing inhalant allergy, (Aerobiology or dissemination of the
allergens), as:
• House dust mites
• Storage mites
• Cockroaches
• Silverfish
Arthropod species causing food-induced allergic reactions, as:
• storage mite species
• Orthoptera—Grasshoppers, locusts, crickets
• Shellfish (Crustaceans)
Direct contact to arthropod allergens, as:
• Caterpillar dermatitis
• Dermatitis linearis
Inoculation of arthropod allergens with, as:
• Saliva during biting (insect bite allergy), or with
• Venom during stinging (insect venom allergy).
Allergies to arthropods occur in these distinct forms.

13. Arthropod
species causing
Inhalant allergy
• House dust mites
• Storage mites
• Cockroaches
• Silverfish
• Chironomids
• Moths and butterflies

14. House dust mites
House dust mite fauna of prominence belong to family
Pyroglyphidae that divided into:
o Subfamily Dermatophagoidinae:
• Dermatophagoides farinae (American house dust mite)
• Dermatophagoides pteronyssinus (European house dust
mite)
• Dermatophagoides microceras (Dust mite)
• Dermatophagoides evansi (mite associated with poultry)
o Subfamily Pyroglyphinae:
• Euroglyphus maynei (Mayne’s house dust mite)
• Euroglyphus longior (Mite infests stored products)
The house dust mites D. farinae, D. pteronyssinus and E.
maynei are cosmopolitan inhabitants of human dwellings.
They are most prevalent in high-use areas in homes (e.g.,
beds, furniture, floors), where shed human skin scales are
collected and serve as a source of food.
Traditionally, the common name “house-dust mite” has
been used collectively to include those members of the
family Pyroglyphidae that are found in association with
house dust.

15. House dust mites; Biology and Habits
• HDM are cosmopolitan in distribution as they are associated with house dust and bird nests.
• HDM have specific environmental requirements for their development. The mites tend to be
most numerous in warm homes with high humidity. Consequently, humidity levels within the
home have a significant effect on survival.
• Osmoregulation of HDM is through their cuticle and therefore require a high ambient air
humidity to prevent excessive water loss. Dust mites cannot survive well at relative humidity
below 50 %.
• Food is seldom a problem for house dust mites. Their primary food is skin scales (dander)
contained in house dust.
• Because the mites feed on dander, dust mites and human association will continue to co-exist
as part of our environment.
• Mattresses, carpets, corners of a bedroom, and floor beneath the bed are favorable dust mite
habitats.
Life cycle:
o House dust mites go through stages of; Egg, Larva, Protonymph, Deutonymoh, Tritonymph
and Adult.
o Between life stages the mites molt, shedding their outer skin.
o When temperature and humidity are optimum, development from egg to adult takes about
one month. The inactive tritonymphs are the mites most likely to survive the decline in
humidity.

16. HDM Allergens:
HDM Allergens are formed in the posterior midgut and the hindgut as digestive enzymes,
excreted in faecal pellets and in shed skins of mites.
Mite fecal pellets, shed skins, and decomposed body parts represent the major source of house
dust mite allergens. The fecal pellets are relatively large and will rapidly fall in undisturbed air,
but in time the pellets will dry and fragmentize to become more easily airborne.
Mite allergens have been well characterized and according to their biological function they are
categorized in more than 20 groups of dust mite allergenic proteins.
Measurement of mite allergens in house dust to give an index of its concentration, and levels of
exposure that represent a risk for the development of asthma.
The major HDM allergens include:
Mite species Allergen
D. pteronyssinus Der p 1, Der p 2
D. farina Der f 1, Der f 2
D. microceras Der m 1
E. maynei Eur m 2

17. HDM Allergy
HDM allergens are involved in three different atopic diseases:
1) Allergic asthma,
2) Allergic rhinitis and
3) Atopic eczema.
About 40% of the human population have a hereditary predisposition to atopy, a
so-called atopic constitution. The inherited atopic constitution is polygenic and
complex. A child inherits a predisposition for:
(1) Atopic disease in general;
(2) Involvement of certain organs; and
(3) Severity of the symptoms.
Discuss; Pathogenesis and clinical aspect of HDM allergy
Guidance:
A. Pathogenesis of atopy (Type1 hypersensitivity)
B. Clinical presentation:
1) Allergic asthma and Allergic rhinitis induced by inhalation.
2) Atopic eczema; The link between HDM allergy and atopic dermatitis is a subject
controversy about induction by inhalation and/or contact.
3) HDM allergy induced by oral ingestion of the allergen is also a subject of suspect.

18. Atopic Dermatitis and HDM
The association between house dust mites (HDMs) and atopic dermatitis (AD) has long been a
matter of contested problem in dermatology, allergy and immunology. In this context, a mechanism
by which HDM may promote AD has been proposed as following:
• Mite allergens are able to activate TH2 cells
• Allergen-specific TH2 cells stimulate production/secretion of periostin by fibroblasts.
• Periostin in turn then stimulates keratinocytes to produce and secrete proinflammatory
cytokines (Thymic Stromal Lymphopoietin (TSLP), and other inflammatory cytokines)
Additionally, it is believed that delayed-type hypersensitivity reactions characteristic of
eczematous AD skin lesions, may result from potentiated ability of Langerhans' cell (LDs) and
dendritic cell (DCs) to process allergens. IgE-bearing DCs present HDM allergens to T cells with
greater efficiency.
Conclusion
The link between HDM allergy and atopic dermatitis (AD) is supported by several laboratory and
clinical studies that have cumulatively shown that:
(1) HDM allergens are able to incite specific and enhanced (LDs) and (DCs) functioning to yield T-
cell–mediated immune responses in AD,
(2) , and HDM allergens have the capacity to polarize immunity toward a Th2 response
(3) At least some subgroup of AD patients with positive HDM patch-test results improve with mite
avoidance and elimination strategies.
Further discussion and investigative pursuits in this arena are necessary.

20. Storage mites
Grain mites
• Storage mites are tiny, white insects that
mostly found in humid and damp
environments but are frequently found in
dry food items such as flour, grains, dried
fruits, cereal, and dry dog and cat foods.
• The droppings of storage mites contain
active enzymes that attack the outer shell of
grains resulting in mould growth. This makes
the grain easier for the mite to eat.
• Storage mites cause allergy and
occupational respiratory disease in those
who handle grains such as farm workers and
bakers.
• The more common genera are
Lepidoglyphus, Tyrophagus, Glycyphagus,
Acarus, Suidasia and Blomia.

21. Several species of storage mites have been shown to cause allergy among rural workers, who to a
varying extent develop asthma, rhinitis or conjunctivitis when exposed to barn dust i.e.,
“occupational exposure”. However, several studies have reported on sensitization to storage mites
also among urban people, indicating that sensitization is not restricted to individuals with
occupational exposure.
Many allergens from storage mites have been described as ‘pan-allergens’, allergens that may
cross species.
Regarding the allergenic relationship between storage mites and house dust mites, there appears
to be a limited allergenic cross-reactivity between the two species. However, both species also
possess their own unique allergens.
Sensitization to storage mites can be initiated through inhalation or ingestion. Moreover, allergic
contact dermatitis results from exposure to mites in grains, dried fruits, flour, and other stored
products, causing itching and redness at the contact sites
storage mites' allergens are involved in the following atopic diseases:
1) Allergic bronchial asthma and rhinitis:  inhalation
2) Allergic conjunctivitis :  contact
3) Atopic skin rash:  contact
4) Oral Mite Anaphylaxis:  ingestion

22. Cockroaches
• Cockroaches are abundant throughout the world
and live in a wide range of environments. They are
social insects and often live in family groups.
• They have unusual reproduction: females lay eggs
in groups of 4-30 bundled together. It looks like one
big egg but is actually many small eggs encased
together in what is called an ootheca. These are
sometimes held protruding from her body or may be
glued in protected areas.
• The diet of Cockroach, which includes
both plant and animal products, ranges from food,
paper, clothing, and books to dead insects,
especially bedbugs.
• Cockroaches can spread a number of diseases to
your family including salmonella and gastroenteritis.
• Cockroaches can be major pests in restaurants,
hospitals, warehouses, offices and buildings with
food-handling areas.

23. American cockroach (species Periplaneta americana), a native of Africa
and the Middle East, is 30 to 50 mm (up to about 2 inches) long, is
reddish brown, and lives outdoors or in dark heated indoor areas.
American cockroach has well-developed wings. However, most species
are not good fliers.
The German cockroach (Blattella germanica), a common household pest, is
light brown with two dark stripes on the prothoracic region. Because it is small
(about 12 mm [less than 0.5 inch] long), this cockroach often is carried into
homes in grocery bags and boxes. It has spread throughout the world thanks
to human transport, including long-distance transport by ship.
The Oriental cockroach (Blatta orientalis) It is also sometimes referred to as the
"black beetle" or a "water bug" because of its dark black appearance and
tendency to harbor in damp locations.It is considered one of the filthiest of
household pests. It is oval, shiny black or dark brown, It is a large species
of cockroach being 25 to 30 mm long.
Types of Cockroaches
The brown-banded cockroach (Supella longipalpa) is a species of small cockroach,
measuring about 10 to 14 mm long. It is tan to light brown and has two light-colored
bands across the wings and abdomen. Although comparable in size to the German
cockroach, they require less moisture and are therefore also found in living rooms
and bedrooms.
There are approximately 4,000 species of cockroaches in the world, and only about four of them most common:
the American cockroach, the German cockroach, the Oriental cockroach, and the Brown-banded cockroach.

24. The saliva, feces and shedding body parts even dead cockroaches can
trigger both asthma and allergies. Cockroach allergens belong to
different families of proteins with distinct structures and biological
activities. Allergenic cockroach proteins can become airborne and cause
allergy symptoms. These allergens act like dust mites, aggravating
symptoms when they are kicked up in the air.
Cockroach allergy has been established as an important cause of
asthma.
Continued exposure to low levels of cockroach allergens in the indoor
environment leads to sensitization in susceptible individuals, and
subsequent exacerbation of symptoms.
Cockroach allergens are involved in three different atopic diseases:
1) Allergic bronchial asthma,
2) Allergic rhinitis and
3) Atopic skin rash.
Cockroach allergy

25. Silverfish (Lepisma
saccharina)
• Silverfish is a small, wingless insect, 1 – 2 cm in
length. It is the most primitive living insect, and
represents a descendent of the ancestral wingless
insects. Its common name derives from the
animal's silvery light grey and blue color.

26. An extract of silverfish has been characterized and the different allergenic
components have been identified Silverfish allergen is tropomyosin (Lep s 1), which
represents the first allergen identified in silverfish extract, and can be regarded as a
molecule cross-reactive among other inhalant and ingested allergens.
Although silverfish have a creepy appearance and are occasionally mistaken for
venomous centipedes, silverfish are not known to bite humans and do not carry
diseases.
They shun light and need a humid environment.
Their diet consists of carbohydrate materials such as paper and book-binding glue,
crumbs of bread and flour.
Symptoms of silverfish allergies include episodes wherein the patients have allergic
rhinitis and allergic bronchial asthma.

27. Moths and
butterflies -
Lepidoptera
• Moths and butterflies belong to the order Lepidoptera, which is Latin for
"scale-wing."
• Moths and butterflies have been implicated as a possible cause of
respiratory allergy.
• The wing scales fall off as the moth flies through the air, creating an
airborne allergen.
• Moths may produce allergens other than their wing scales. The excrement
of a moth ,If inhaled, can elicit an allergic reaction. In addition, direct
contact with many species of moths can cause skin irritation, due to the
presence of urticating scales on the underside of the abdomen. These spiky
scales can imbed into the skin, causing severe inflammation and itching. If
inhaled, urticating scales can cause asthma.

28. Chironomid (chironomids, nonbiting midges, or lake flies)
Chironomids (nonbiting midges) inhabit natural rivers, lakes, and ponds as well as artificially dammed pools.
The Chironomidae are important as indicator organisms, i.e., the presence, absence, or quantities of various
species in a body of water can indicate whether pollutants are present.
Because adults have a short life span and weak bodies when debris from their bodies is mixed with dust or the
air, this debris can then enter the nasal cavity or bronchus during breathing and cause allergies. Hemoglobin
are unique components of chironomid larvae and have been identified as potent allergens found in patients
with allergies. However, since hemoglobin are observed only in chironomid larvae, not adults, it is anticipated
that other antigens from adult chironomids may induce allergic reactions such as asthma.

29. • Storage mite species
• Shellfish: Crustaceans
and Mollusks
• Edible insect:
o Orthoptera: Grasshoppers
and Crickets
o Coleoptera: Yellow
mealworm beetle
Arthropod species
causing food-induced
allergy

30. Oral Mite Anaphylaxis
(OMA)
(Pancake Syndrome)
The disease name “Pancake Syndrome” comes
from reports of people becoming ill after
eating pancakes made from contaminated flour.
Because cooked foods are able to induce the
symptoms, it has been proposed that thermo-
resistant allergens are involved in its production.
Since 1993 clinical reports began to document cases of
severe allergic reactions from baked food made with
mite infested wheat flour.
In 2009 the World Allergy Organization recognized this
phenomenon by publishing a paper on the subject, it is
called 'Pancake Syndrome', or oral mite anaphylaxis
(OMA).
Storage mite species

31. Many cases of OMA can go undiagnosed or listed as unexplained. To counter this a comprehensive
list of the known risks have been made:
1. Previous atopic disease;
2. Mite sensitization;
3. NSAID hypersensitivity;
4. Ingestion of pancakes or other meals containing wheat flour;
5. Ingestion of more than 1 mg of mite allergen (>500 mites per gram of flour).
The symptoms of OMA are common to anaphylaxis.
Symptoms include vomiting, breathlessness, wheezing, coughing, itching, skin rash, angioedema
etc. Symptoms typically appear within the first 10 to 45 minutes after ingestion.
Prophylaxis: Because the exposure to low temperatures inhibits mite proliferation, the
recommendation has been made to store the flour in sealed plastic or glass containers in the
refrigerator will prevent.
Exercise-induced anaphylaxis as a result of eating pancakes contaminated with dust mites,
followed by playing soccer, has also been reported
Treatment of anaphylaxis by taking medication such as injectable epinephrine, antihistamines,
and corticosteroids.
Different storage mite species are present in the flours producing OMA. Among them (Blomia
tropicalis, Tyreophagus entomophagus, and Suidasia pontifica).
Oral Mite Anaphylaxis

32. • Shellfish
• Many varieties of shellfish are closely
related to insects and arachnids, making up
one of the main classes of the phylum
Arthropoda.
• Shellfish live in the water and have a shell
(or shell-like) exterior. Shellfish can be
divided into two main categories:
crustaceans and mollusks.
• Crustaceans: Characterized by hard outer
shells and segmented limbs, examples of
commonly enjoyed crustaceans are shrimp,
crab and lobster.
• Mollusks: Defined as soft-bodied
invertebrates with calcium carbonate shells,
examples of commonly enjoyed mollusks are
clams, mussels, scallops and oysters.

33. Shellfish allergies are the most common food allergies in adults and among the most common food
allergies in children. Shellfish allergies are usually lifelong.
Once an allergic reaction has occurred it usually remains a lifelong sensitivity. The immune system
overreacts to proteins found in shellfish, most commonly to tropomyosin, but often to other proteins,
such as arginine kinase, myosin light chain and sarcoplasmic calcium-binding protein.
The allergic reaction to fish is to a different protein, parvalbumin; so, there is no cross-reactivity
between fish and shellfish allergy.
Cross-reactivity to non-shellfish
Tropomyosin, the major allergen in shellfish allergy, is also found in dust mites and cockroaches.
Exposure to inhaled tropomyosin from dust mites is thought to be the primary sensitizer for shellfish
allergy, an example of inhalant-to-food cross-reactivity.
Food-dependent, exercise-induced anaphylaxis:
Exercise can be a contributing factor to an allergic food response. when the food in question is
consumed within a few hours before high-intensity exercise, the result can be anaphylaxis. One
theory is that exercise is stimulating the release of mediators such as histamine from IgE-activated
mast cells. However, Exercise is not essential for the development of symptoms, but rather that it is
one of several augmentation factors, as alcohol or aspirin resulting in a respiratory anaphylactic
reaction.
The manifestations of shellfish allergy develop within minutes after eating. The allergic
manifestations similar to OMA, but it tends to be more severe.
Treatment: In mild or moderate allergic reaction, antihistamines can reduce your symptoms.
In the case of a moderate or severe allergic reaction to shellfish, an injectable epinephrine can
reverse symptoms by opening the airways and stabilizing blood pressure.

34. • Order Orthoptera: Grasshoppers and Crickets
• Order Coleoptera: Yellow mealworm beetle
• Order Lepidoptera: Domestic silkworm
• Edible insects:

35. • Mealworms are the larval form of
the yellow mealworm beetle,
Tenebrio molitor (order Coleoptera).
Allergies to mealworms are of
relevance especially in owners of
animals who use them as animal feed
or bait. After inhalative or
transcutaneous sensitization, allergic
symptoms such as rhinoconjunctivitis
or respiratory symptoms may occur.
Tropomyosin-mediated cross-allergies
to mealworms after ingestion as well
as genuine mealworm food allergies
are possibl
Coleoptera

36. Lepidoptera
• Pupae of the Domestic silkworm moth
(Bombyx mori) are an important by-product of
sericulture and have a long history as food
and feed ingredients in East Asia. Silkworm
pupae are a good source of protein, lipids,
minerals, and vitamins and are considered a
good source of nutrients for humans. Because
silkworm pupae are being increasingly used in
the human diet, potential allergic reactions to
the substances they contain must be
elucidated.
• Allergic reactions after consuming
silkworm pupae include urticaria, dizziness,
skin itching, and shock.
• The main protein characterized as an
allergen in silkworm pupa was an arginine
kinase (which cross-reacted with an arginine
kinase in cockroaches), tropomyosin,
chitinase, and triosephosphate isomerase are
also allergens.

37. • Various species of order Orthoptera are
consumed as food worldwide.
• Cricket and grasshopper are roasted, grilled, or
fried and are nowadays considered to be one of the
most promising insect species for global
consumption because they have a beneficial
nutritional profile.
• The house is farmed in South-East Asia and parts
of Europe and North America for human
consumption. The house cricket was approved as
novel food in frozen, dried and powdered forms
• However, allergic reactions to Orthoptera,
especially in seafood or house dust mite sensitized
patients are possible and may be caused by
tropomyosin cross reactivity. In principle, however,
genuine food allergies and not only cross-allergies to
Orthoptera are possible.
• Cricket allergy is less severe and less common
than allergy to locusts and grasshoppers. A partial
cross-reactivity exists between cricket and
grasshopper allergens.
• Cricket allergens are proteinaceous compounds,
but their nature is insufficiently known; arginine
kinase and hexamerin 1B may play a role.
Orthoptera

38. Inoculation of arthropod allergens with;
• Saliva during biting (insect bite allergy), or
• Venom during stinging (insect venom allergy).
There are many different kinds of insects that can cause allergic reactions by stinging and/or biting:
Stinging Insects
Bees, wasps, hornets, yellow-jackets and fire ants are the most common stinging insects that
cause an allergic reaction.
• When these insects sting man, they inject a toxic substance called venom. Most people stung
by these insects recover within hours or days.
• In others, this venom can trigger a life-threatening allergic reaction. A toxic
reaction happens when the body reacts to insect venom. It is serious but non-allergic
reactions. A toxic reaction can cause symptoms similar to those of an allergic reaction. With
other symptoms include nausea, fever, fainting, seizures, shock and even death.
Biting Insects
Mosquitoes, kissing bugs, bedbugs, fleas, lice and certain flies are the most common biting
insects known to cause an allergic reaction.
Most people bitten by insects suffer pain, redness, itching, stinging and minor swelling in the area
around the bite. Rarely, insect bites may trigger a life-threatening allergic reaction (anaphylaxis).

39. Insect bite allergy
• Mosquitoes,
• Horseflies
• Black Flies
• deer fly
• Sand Fly
• Biting midges
• fleas,
• Lice,
• kissing bugs,
• bedbugs,
Inoculation of arthropod
allergens with Saliva
during biting

40. Biting Insects
Mosquitos
• When they bite you, they inject saliva into your body while siphoning your
blood. Their saliva contains proteins that most people are allergic to. Almost
immediately after a mosquito bites you, you may notice a round and puffy bump
forming.
• In some cases, you may see a small dot at the center of it.
• The bump will soon become red and hard, with a small amount of swelling.
It’s not uncommon to get multiple bites around the same time.
• If you have an impaired immune system, you may experience a more severe
reaction, such as hives, a large patch of swelling and redness, or swollen lymph
nodes. Children often get a stronger reaction than adults.

41. • Horseflies are large and may have green heads or be completely black. They are strong
fliers and a serious nuisance of warm-blooded animals and people. Only the females
require a blood meal. Their mouthparts are blade-like and it is painful when they cut
through the skin. When the blood is flowing from the wound they will "lap" it up.
• A bite from a horsefly can be very painful and the bitten area of skin will usually be red
and raised.
Genus: Tabanus (biting Horseflies)

42. Simulium ( Black Flies, Buffalo Gnats)
• Black flies small (1/16 to 1/8 in. long), bloodsucking flies that are usually black to gray in color.
• Black flies may fly up to 10 miles in search of blood.
• Black fly bites often cause considerable swelling and bleeding, may be itchy and slow to heal. They
prefer to attack the head and where clothing fits tightly.
• Injury from black fly bites can threaten the lives of livestock and even people when present in very
large numbers. Deaths have been reported from allergic reactions and blood loss from the bites.

43. Chrysops (deer fly )
• The female deer fly bite involves two
pairs of mouthpart “blades” that the fly
uses to cut the skin. Once the skin is
injured, blood begins to flow, and the
female then uses other mouthpart
components to lap up and ingest the
exposed blood. The general signs and
symptoms of deer fly bites are:
o Localized symptoms including swelling
and an itchy red area around the bite.
o Since deer flies inject anticoagulant-
containing saliva during blood feeding,
some life-threatening serious reactions
may occur in people that are highly
allergic to the anticoagulant
compounds. Symptoms may include a
rash on the body, wheezing, swelling
around the eyes, swelling of the lips and
dizziness or weakness.

44. Ceratopogonidae is a family of flies
commonly known as “No-see-ums”,
“Punkies,” or ”Biting midges”.
• Midges are often mistaken for
mosquitoes, but; midges small ( 1–3 mm),
fly in swarms that look like clouds. Midges
don't have a biting needle (proboscis) but,
their mouthparts are well-developed for
cutting the skin of their hosts.
• Midge bites look like mosquito bites.
However, it’s not easy to spot a midge
biting you, but you are only left with a
sharp sting or burning sensation as the
aftermath of the bite.
• A midge bite is often a tiny, red, itchy
bump. If watched closely, a small hole can
also be spotted within the bump where the
bite has punctured the skin. Cases have
also been reported of developing fluid-
filled blisters around the edge.
Family:
Ceratopogonidae (Biting midges)

45. Phlebotomus (Sand Fly)
• Sandfly is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly)
encountered in sandy areas. The bite of the sandfly when observed on the human skin has the tell-
tale mark of a small swollen and blotchy patch in vivid red. Though most bite is small and leaves no
reaction, certain individuals that suffer from allergic reactions tend to develop severe itching around
the left over the mark. These people are also seen to develop swollen welts around a given region of
the bites in clusters that are purple and red in color. Though the typical bite takes approximately a day
or two to heal and another few days to completely disappear.

46. Siphonaptera
Fleas
• Fleas : any of an order (Siphonaptera) of small wingless
bloodsucking insects that have a hard laterally compressed body and
legs adapted to leaping and that feed on warm-blooded animals
• Flea bites look like little mosquito bites. They have a lightly raised
red area which may be somewhat swollen. In addition, they will have a
small puncture mark in the middle that looks like a little dot. Common
places to find flea bites are inside knees and elbows, armpits, neck,
waist, and ankles. The bites will usually be in a group (cluster) in the
same area.

47. Pediculus
humanus capitis
(Head louse )
• Head lice are the only bugs that live in human hair. After a full month
of having head lice, most people’s heads begin driving them crazy. The
itch is a deep internal nagging that you just can’t seem to scratch
enough to satisfy.
• Allergic reaction to lice saliva is a rash or red bumps. For many
people, this sign can show up even before the itching begins. Many
people term this "lice bites." In reality, these aren't actually lice bites, it's
just another allergic reaction to lice saliva.

48. Pediculus humanus
humanus
(body louse)
• Body lice live in your clothing and
bedding and travel to your skin several
times a day to feed on blood. The most
common sites for bites are around the
neck, shoulders, armpits, waist and groin
— places where clothing seams are most
likely to touch skin. Common symptoms
include:
• Itchy and irritated skin.
• Groups of small, discolored (red,
purple, brown) rash caused by
an allergic reaction to body lice bites
They may grow bigger and develop a
lighter discolored ring around the
outside.

49. • Triatoma is a genus of assassin bug in
the subfamily Triatominae (kissing bugs).
The members of Triatoma are blood-
sucking insects that can transmit serious
diseases, such as Chagas disease.
• People who are sensitive to the kissing
bug’s saliva may experience a reaction to
the bite. This is usually only
mild itching, redness, and swelling.
Occasionally, a kissing bug bite causes
a severe localized allergic reaction.
• Their saliva may also trigger severe
allergic reactions in sensitive individuals,
up to and including severe anaphylactic
shock.
Triatomine
(kissing bug)

50. Bedbugs,
Cimex lectularius
• Bed bug bites on the other hand
can occur anywhere on exposed
body parts and often appear in a
linear pattern, as a series of multiple
bites in a row.”
• Bed bug bites often have a little
bloody spot or reddish bruise in the
middle. They’re typically slightly
larger than flea bites,
• It’s even possible to have an
allergic reaction to bed bug bites —
but only in the rarest cases and
major infestation has anyone
experienced true anaphylaxis.

51. Hymenoptera Venom
Allergy
The species that are medically important belong to three
families:
1) Apidae, (Bee: Honeybee and Bumblebees).
2) Vespidae, (Wasp: common wasp, yellow jacket and
hornet).
3) Formicidae, (Ant: fire ant, bullet ant and thief ant).
• Only the females of each species have stingers, which are
ovipositors that have lost their egg-laying function and have
been modified for stinging and envenomation.
• Most species sting in defense of themselves and their nests,
although some species also sting as a means of capturing their
prey.
• Venoms of Hymenoptera are aqueous solutions containing
proteins, peptides, and vasoactive amines. Collectively, these
components have toxic properties. In addition, several of the
venom proteins are allergenic.
• Hymenoptera venom allergy is an (IgE)- mediated
hypersensitivity. This allergic reaction may be caused by stings
from several species in this insect order and occurs only in
person who have previously been sensitized to Hymenoptera
venom.
Stinging
Insects

52. Most insect stings cause mild local reactions for which no specific treatment is usually required.
Some local reactions are manifested by extensive swelling surrounding the sting site that can
persist for several days or more and might be accompanied by itching, pain, or both. Cold
compresses might help to reduce local pain and swelling. Oral antihistamines and oral analgesics
might also help to reduce the pain or itching associated with cutaneous reactions
Large local reactions are usually IgE mediated but are almost always self-limited and rarely create
serious health problems. Patients who have previously experienced large local reactions often
have large local reactions to subsequent stings, and up to 10% might eventually have a systemic
reaction. Most patients with large local reactions need only symptomatic care and are not
candidates for testing for venom specific IgE or venom immunotherapy
Systemic reactions can include a spectrum of manifestations not contiguous with the site of the sting,
ranging from mild to life-threatening. These may include the following:
• Cutaneous (eg, urticaria, angioedema, itching, flushing)
• Bronchospasm
• Upper airway obstruction (eg, tongue or throat swelling and laryngeal edema)
• Cardiac (eg, arrhythmias and coronary artery spasm)
• Hypotension and shock
• Gastrointestinal (eg, nausea, vomiting, diarrhea, and abdominal pain)
• Neurologic (eg, seizures)

53. Family Apidae:
Bees
• Domestic honeybees are found in commercial hives, whereas
nondomestic honeybees nest in tree hollows, old logs, or in
buildings.
• Africanized honeybees are hybrids that developed from
interbreeding of domestic honeybees and African honeybees.
Africanized bees pose an even bigger threat to your home or
business if they build their hive in your yard or on the side of your
building.
• Bumblebees are very uncommon causes of sting reactions but
have been reported to cause anaphylaxis during occupational
exposure in greenhouse workers

54. Family
Vespidae:
Wasp
• Yellow jackets, hornets, and wasps are in the vespid family and feed on
human foods.
• They are especially attracted to sweet food, fruit, and grilled food.
Consequently, they can be found around garbage cans, leftover food, or at
outdoor events where food and sweet drinks are served.
• Yellow jackets are very aggressive and sting with minimum provocation.
People have been stung in the mouth, oropharynx, or esophagus while
drinking a beverage from a container that contained a yellow jacket. Hornets
build large paper-enclosed nests that are usually found in shrubs and trees.
Hornets attack honeybee hives, killing adult bees and devouring bee larvae
and pupae, while aggressively defending the occupied colony. Their stings
are big and painful,. Multiple stings can kill humans, even if they are not
allergic

55. Prevention:
People at risk of insect sting anaphylaxis should be:
• Educated regarding measures to avoid insect stings,
• Have an epinephrine auto-injector immediately available, and
• Consider venom-specific immunotherapy, which can effectively treat venom allergy in most patients.
Classification of systemic allergic reactions to bee or wasp stings
Severity Symbol Reactions
Mild + Erythema, pruritus, urticaria, angio-oedema, rhinitis, nausea
Moderate ++ Asthma, angio-oedema, abdominal pain
Severe +++
Respiratory difficulty (laryngeal oedema or asthma), marked hypotension,
collapse, loss of consciousness
Treatment:
• Remove bee stingers within 20 to 30 seconds after being stung to limit the
amount of venom entering your body. Use a scraping, as opposed to pulling
motion, to extract the stinger without squeezing more venom into the skin.
• Ice the area to control swelling, and if stung in the arm or leg, elevate the
area.
• Employ acetaminophen or ibuprofen to help ease pain.
• Control itching with an antihistamine, ice, hydrocortisone cream, or
calamine lotion.
• Employ topical corticosteroid ointments and oral antihistamines to relieve
itching associated with fire-ant stings.

56. Formicidae,
Ant:
Fire ant &
Bullet ant.
• Fire ant can be red (Solenopsis invicta) or black
(Solenopsis richteri).
• Solenopsis invicta is one of the most talked about, mostly
because of how much damage they have caused. They are
also known as ‘Red imported fire ants’ (RIFA).
• Paraponera clavata is a species of ant, commonly known
as the bullet ant, named for its extremely painful sting.

57. Images linked below are used in the animated photos of a person's finger after a fire ant sting:
• Stinging photo: A worker female fire ant in the act of stinging a human thumb.
• 30-minute photo: There is a slight swollen bump where each sting occurred, surrounded by redness.
• One hour photo: The bumps persist, and the surrounding redness gets deeper red.
• 24 hours photo: A pustule is now present where each sting occurred. Lesions are still surrounded by a deep red halo.
• 72 hours photo: Pustules are at their peak, with a deep red halo, and some tissue death inside the tiny pustule
domes.
• One week photo: By now the pustules have ulcerated; the red halo persists.
• One month: Only superficial scars remain where the stings occurred.

58. Formicidae, (Ant:
Thief or Worker ant)
• This species is a thief ant and usually has its
nest near another species, stealing food by
entering the foreign colony through minute
tunnels dug from their own nest.
• Length 1.5-3 mm, yellow to brownish
yellow; Body and appendages with numerous
hairs
• the ant venom, which is injected from a
poison gland located at the posterior end of the
ant (gaster) and contains several irritating
substances The most important fraction of the
ant venom is known as “solenopsin”, which may
trigger distant allergic reactions in atopic
patients. In this case, widespread eruptions
(beyond the areas of bites) and the lack of a
true pustulous eruption strongly suggest a
hypersensitive phenomenon,

59. Health problems linked with tick bites include:
• Allergic reactions.
• Allergic reactions to red meat (mammalian meat
allergy).
• Transmission of infections
• Tick paralysis
• Mild allergic reactions to ticks appear as large
local swelling and inflammation at the site of a
tick bite, that can last for several days.
• Severe allergic reactions (anaphylaxis) to the
Australian paralysis tick, Ixodes holocyclus have
been reported. Anaphylaxis occurs when the tick
is disturbed, as this causes the tick to inject more
allergen-containing saliva.
• It is important to avoid disturbing the tick by
scratching something that can’t be seen, trying to
remove the tick, or applying chemicals such as
methylated spirits or kerosene to the tick.
Order Ixodida (Ticks)

60. • A bite from a Lone Star Tick (Amblyomma americanum )
can cause people to develop an allergy to meat. These ticks
carry alpha-gal (a sugar). When a tick bites a person, it
transfers alpha-gal into the bloodstream. The person’s
immune system then reacts to it.
• Alpha-gal is also found in mammal meat (beef, lamb, pork).
Some people will also be allergic to mammalian milks and
animal-derived gelatin which is present in many food
products, as a binding agent in some medications and in
intravenous blood substitutes known as gelatin colloid
This allergy is characterized by a delayed reaction appearing 4–8
hours after consumption of the meat. AGS reactions can include:
• Hives or itchy rash
• Nausea or vomiting
• Heartburn or indigestion
• Diarrhea
• welling of the lips, throat, tongue, or eye lids
• Dizziness or faintness
• Severe stomach pain
Alpha-gal allergy or Mammalian Meat
Allergy (MMA),

61. Caterpillars Lepidopterism
• Caterpillars are the larvae (immature forms) of butterflies and
moths. They look like worms and are covered in small hairs. Most are
harmless, but some can cause allergic reactions, especially in contact
with their hairs, or if you eat them.
• Lepidopterism" is the term for a variety of cutaneous and systemic
reactions that result from contact with larvae (ie, caterpillars) or adult
forms of moths and butterflies (order, Lepidoptera)
• The primary clinical manifestations of lepidopterism include sting
reactions, hypersensitivity reactions, and lonomism (a potentially life-
threatening hemorrhagic diathesis). The most frequent clinical
manifestation caused by caterpillar envenomation is the development
of contact dermatitis, characterized by an extensive local inflammatory
process with swelling, redness and an itch at the site of envenomation.
• One of the targets of caterpillar venom component(s) are mast cells.
Mast cells are known to cause adverse skin reactions and play an
important role in the pathogenesis of allergy, dermatitis,
DIRECT CONTACT TO
ARTHROPOD ALLERGENS,

62. • Blister beetles get their name from a caustic chemical they produce called cantharidin which is a
potent blistering agent. Cantharidin also can have severe medical consequences and widely is viewed as
a poison. General handling of adults seldom results in blistering unless the hemolymph contacts the skin.
Hemolymph is often exuded when an adult beetle is pressed or rubbed initiating allergic reactions.
• Symptoms vary from severe, but temporary, pains to large blisters commonly occur on the neck and
arms within 2-3hours of contact with human skin. The blistering while uncomfortable, was not painful.
• Treatment beyond first aid is probably not necessary as the blisters soon diminished on their own.
Blister Beetle: Blistering Dermatitis
Order Coleoptera: Beetles

63. Rove beetles (Paederus beetles):
Paederus dermatitis
Paederus species are widely distributed around the world. It is approximately
1cm in length, active during the day and attracted to bright lights after
nightfall. These red and black insects can neither sting nor bite, but they can
cause a skin irritation known as Paederus dermatitis, when crushed against the
skin. This is because their haemolymph contains pederin, which is a potent
toxin.
The temptation when feeling a beetle on one's skin is to brush it off. That’s
the worst thing you can do with this insect, as its crushing would lead to
severe dermatitis. Different responses are seen in the skin depending upon
its concentration, duration of exposure, and individual characteristics.
Mild cases, there is a slight erythema lasting for 2 days.
Moderate cases, the erythema evolves into vesicles and bullae over a few days, followed by a
squamous stage when the blisters dry out over a week, and then a stage when they desquamate,
leaving hyper or hypopigmented patches.
Severe cases, in addition to showing more extensive blistering, may have additional symptoms
such as fever, neuralgia, arthralgia, and vomiting..

64. a) The lesions are characteristically linear (Linear Dermatitis) due to
smearing the crushed insect across the skin.
b) A Kissing Lesion: occurs when the Rove beetle is crushed between a
joint flexure causing identical mirror lesions.
c) Periorbital involvement: probably secondary to spread of pederin to
the eyelids by the hands ‘Nairobi eye’.
Paederus dermatitis
Affected individuals may inadvertently transfer paederin to other
areas of the body, such as the genitals or the face. If the periorbital
area is affected, conjunctivitis may develop (referred to ‘Nairobi
eye’ in eastern Africa).
Treatment
Initially involves removal of the irritant by washing the area with soap and
water. The blistered site should be treated with cool wet soaks, followed
by a strong topical steroid and antibiotics.
An interesting study was preformed in Sierra-Leone. Half of the patients
were given oral ciprofloxacin in addition to the topical steroid. Healing
time was statistically faster in these patients, which suggests a concurrent
bacterial infection was present, most likely from the Pseudomonas the
Paederus beetle harbors.

65. Millipedes: meaning a thousand legs. They have an elongated
body composed of various segments with two pairs of legs in
each. Some millipedes secrete a toxin on their skin as a
defensive mechanism, other release toxins when pressed or
crushed. Some large species can squirt secretions from
distances up to 32 inches.
Millipedes often enter homes and retreat to dark places,
which is why many victims are bitten while putting on a shoe.
Signs and Symptoms; Dermatitis (itching and burning) that
begins with hyperchromic lesions on the skin. Secretions in
the eye can cause immediate pain, lacrimation and blurry
vision.
Treatment; Wash skin with soap and water. If the eye is
affected, irrigate with water or saline, and ophthalmologic
evaluation is recommended.
Millipedes are a group of arthropods that are
characterized by having two pairs of jointed legs on most
body segments; they are known scientifically
as class Diplopoda, subphylum Myriapoda (that contains
millipedes and centipedes). Although their name suggests
they have myriad (10,000) legs, myriapods range from
having up to 750 legs to having fewer than ten legs.
Millipedes

66. • Centipedes: meaning a hundred legs.
• Centipedes are carnivorous arthropods that also have a
segmented body but have only one pair of legs on each
segment. The first segment has two large forcipules that
originate from the first pair of legs, which can inject venom
contained in glands in the trunk of the animal and can be
used in defense or to catch prey.
• The Scolopendra genus reaches up to 25cm long and
causes the most serious injuries.
Signs and Symptoms;
• The bite of a centipede causes intense pain, with local
erythema and edema.
• Superficial necrosis and ulceration may occur.
• In some cases, headache, malaise, anxiety, and dizziness are
also observed.
• Almost all cases spontaneously resolve without
complications.
Treatment: The site of the bite should be washed with soap
and water, and cold compresses are useful. Systemic
analgesics are recommended to control the pain.
Centipedes

67. The next lecture:
Management of
Arthropod
Allergens
D. Ibrahim
Abouelasaad