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Insect allergy

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Insect allergy
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Insect allergy

  1. 1. Insect Allergy Prof. Dr. Saad S Al Ani Senior Pediatric Consultant Head of Pediatric Department Khorfakkan hospital Sharjah ,UAE Saadsalani@yahoo.com
  2. 2. History The 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 19 April 2013 2 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  3. 3. Introduction Allergic responses to stinging 1. Localized cutaneous reactions 2. Systemic anaphylaxis 19 April 2013 3 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  4. 4. 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 19 April 2013 4 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  5. 5. 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. 19 April 2013 5 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  6. 6. 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. 19 April 2013 6 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  7. 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. 19 April 2013 7 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  8. 8. Cont. Systemic reactions to stinging insects occur in 0.4- 0.8% of children and 3% of adults 19 April 2013 8 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  9. 9. Cont. Members of the order Hymenoptera include: i. Apids: * Honeybee * Bumblebee ii. Vespids * Yellow jacket * Wasp * Hornet iii. Formicids * Fire ants * Harvester ants 19 April 2013 9 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  10. 10. Species of Hymenoptera and their geographical distribution. Freeman TM: Hypersensitivity Hymenoptera stings, N Engl J Med 351:1978–1984, 2004.) 19 April 2013 10 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  11. 11. Cont. Freeman TM: Hypersensitivity Hymenoptera stings, N Engl J Med 351:1978–1984, 2004.) 19 April 2013 11 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  12. 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 19 April 2013 12 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  13. 13. Cont. Systemic IgE-mediated allergic reactions to salivary proteins of biting insects such as mosquitoes are reported but uncommon. 19 April 2013 13 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  14. 14. 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 19 April 2013 14 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  15. 15. 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 19 April 2013 15 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  16. 16. Perennial allergy Attributed to sensitization to insects such as cockroaches and ladybugs as well as house dust mite 19 April 2013 16 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  17. 17. 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 19 April 2013 17 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  18. 18. Cont. The majority of patients who experience systemic reactions after Hymenoptera stings have IgE-mediated sensitivity to antigenic substances in the venom. 19 April 2013 18 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  19. 19. 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.com 19 April 2013 19 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  20. 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. http://www.theonlineallergist.com 19 April 2013 20 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  21. 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. http://www.theonlineallergist.com 19 April 2013 21 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  22. 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 http://www.theonlineallergist.com 19 April 2013 22 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  23. 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 http://www.theonlineallergist.com 19 April 2013 23 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  24. 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 two Scratching these pustules can lead to local infection and scars It is not unusual to sustain multiple bites, generally on the feet and hands http://www.theonlineallergist.com 19 April 2013 24 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  25. 25. 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 19 April 2013 25 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  26. 26. Clinical reactions to stinging venomous insects Are categorized as: 6.Delayed/Late 1. Local 2. Large local 3. Generalized cutaneous 4. Systemic 5. toxic 19 April 2013 26 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  27. 27. 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 19 April 2013 27 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  28. 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. Hypotension 19 April 2013 28 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  29. 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 insects 19 April 2013 29 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  30. 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 19 April 2013 30 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  31. 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 19 April 2013 31 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  32. 32. 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 19 April 2013 32 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  33. 33. 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 negative 19 April 2013 33 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  34. 34. The diagnosis of inhalant insect allergy May be evident from a history of typical symptoms induced seasonally in specific geographic regions Skin prick or in vitro immunoassay tests for specific IgE to the insect are used to confirm inhalant insect allergy 19 April 2013 34 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  35. 35. Treatment i. Cold compresses ii. Topical medications to relieve itching iii. occasionally the use of a. systemic antihistamine b. oral analgesic are appropriate Stingers 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 19 April 2013 35 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  36. 36. Cont. Sting sites rarely become infected, possibly owing to the antibacterial actions of venom constituents Vesicles left by fire ant stings that are scratched open should be cleansed to prevent secondary infection 19 April 2013 36 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  37. 37. Cont. Therapies may include: i. Oxygen ii. Epinephrine iii. Intravenous saline iv. Steroids v. Antihistamines Anaphylactic reactions 19 April 2013 37 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  38. 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 19 April 2013 38 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  39. 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 yr Positive result 20 Yes Negative result — No Systemic reaction Any Positive result Child: 40 Adult: 60-70 Yes Negative result — Usually no *Risks generally decrease after 10 yr 19 April 2013 39 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  40. 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 19 April 2013 40 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  41. 41. Cont. Typical insect repellents do not guard against Hymenoptera. Nests of these insects should be removed if they are close to the home 19 April 2013 41 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  42. 42. Cont. Individuals who have had generalized cutaneous or systemic reactions to Hymenoptera stings should have immediate access to self- injectable epinephrine The individual at risk for anaphylaxis from an insect sting should also wear an identification bracelet indicating the allergy 19 April 2013 42 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  43. 43. Cont. Avoidance of the insect is the preferred management of inhalant allergy Immunotherapy is occasionally undertaken in such cases, but beneficial results have not been thoroughly documented. 19 April 2013 43 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE
  44. 44. References 19 April 2013 44 Insect Allergy Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE 1. http://www.acaai.org/allergist/allergies/types/inse ct-sting-allergies 2. http://www.theonlineallergist.com 3. 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.com 7. 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

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