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Hypersensitivity

Allergic Reaction

An allergy is defined as an immune response induced by exposure to an allergen. Austrian pediatrician Clemens Pirquet first used the term allergy in 1906. Hypersensitivity reactions can be divided into four groups: type I, type II, type III and type IV, based on the mechanisms involved.


Presentation

Symptoms of type1 hypersensitivity reactions might vary from mild to severe. Allergen exposure in the beginning might cause mild symptoms, which might get worse when exposed to the allergen. Symptoms of the mild allergic reaction include itching, rashes, hives, nasal congestion, rhinorrhea, sneezing, dyspnea, wheezing and itchy eyes.

Easy Bruising
  • Among 27 possible risk factors assessed, statistically significant associations included recurrent epistaxis, easy bruising, hypersensitivity (eczema, hives, hay fever, and rhinitis), previous treatment with sclerotherapy or endovenous laser for lower[ncbi.nlm.nih.gov]
Sneezing
  • Symptoms: Some of the symptoms of type1 hypersensitivity are nasal congestion, sneezing, wheezing, rashes, hives and itchy eyes.[symptoma.com]
  • Metal hypersensitivities have a delayed onset from the time of exposure to the materials and are not caused by specific antibodies or histamine release that lead to the classical indications of a common allergy like itching, watery eyes, or sneezing.[center4research.org]
  • A more mild form would include Allergic Rhinitis (seasonal allergies) that cause things like coughing, sneezing, watery eyes and nasal congestion.[stomponstep1.com]
  • Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes , swelling, or asthma . Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening.[fpnotebook.com]
Pleural Effusion
  • A chest X-ray showed hazy opacity with prominent reticulation within the upper lung fields bilaterally, right greater than the left with no pleural effusion. Lung computed tomography revealed nonspecific bilateral upper lung opacification.[ncbi.nlm.nih.gov]
Fever
  • A young Japanese woman presented to our hospital with relapsing respiratory symptoms accompanied by high fever. A detailed interview revealed that the onset of the symptoms occurred shortly after using a humidifier in her home.[ncbi.nlm.nih.gov]
  • On the second occasion, re-introduction resulted in whole body rash 4 h post dose and was associated with fever, respiratory symptoms, headache and vomiting. On examination, he was pyrexic, tachyponeic, tachycardiac and hypotensive.[ncbi.nlm.nih.gov]
  • He was admitted to a referral hospital after one month of working, and exhibited a fever with skin symptoms.[ncbi.nlm.nih.gov]
  • All participants with immunologically confirmed hypersensitivity reactions had multiple symptoms: about two-thirds had the presence of at least three symptoms (fever, rash, plus another systemic symptom) and a third consisted of fever plus rash alone.[aidsmap.com]
  • Among 27 possible risk factors assessed, statistically significant associations included recurrent epistaxis, easy bruising, hypersensitivity (eczema, hives, hay fever, and rhinitis), previous treatment with sclerotherapy or endovenous laser for lower[ncbi.nlm.nih.gov]
Malaise
  • Clinical Spectrum The most common symptoms of abacavir hypersensitivity are fever, rash, nausea, vomiting, diarrhea or abdominal pain, and fatigue and malaise [ 53 ].[academic.oup.com]
  • ., tachycardia, hypotension, myalgia, fatigue, pain, malaise, dizziness, and headache), findings that are consistent with those previously reported.[nejm.org]
Red Eye
  • Symptoms may include red eyes, an itchy rash, sneezing, a runny nose, shortness of breath, or swelling. Food intolerances and food poisoning are separate conditions. Common allergens include pollen and certain food.[en.wikipedia.org]
Urticaria
  • The authors present 2 case reports of selective cefazolin hypersensitivity: a 49 year-old woman with a history of two perioperative reactions (urticaria and severe anaphylaxis) after the use of rocuronium, propophol and cefazolin; a 36 year-old pregnant[ncbi.nlm.nih.gov]
  • These skin reactions include perioral dermatitis, stomatitis, and urticaria.[fluoridealert.org]
  • […] hypersensitivity syndrome, work-up, and management Identify the classic morphologic findings and triggers for erythema multiforme Distinguish between erythema multiforme and other hypersensitivity reactions in children including serum sickness like reaction and urticaria[aad.org]
  • […] hypersensitivity reaction an inappropriate and excessive reaction to an allergen (as pollen or dust or animal hair or certain foods); severity ranges from mild allergy to severe systemic reactions leading to anaphylactic shock hives , nettle rash , urticaria[vocabulary.com]
  • Urticaria , pruritus , edema , hypotension , or even symptoms of anaphylactic shock Diagnosis and treatment Infection-induced urticaria References: [34] [35] [36] [37] [38] [39] The differential diagnoses listed here are not exhaustive.[amboss.com]
Eruptions
  • Adverse drug reactions of the delayed type rank among the most common dermatoses and are predominantly characterized by exanthematous macular or maculopapular eruptions.[ncbi.nlm.nih.gov]
  • The remaining articles reported Steven-Johnson syndrome/toxic epidermal necrolysis, fixed drug eruptions, and cross-intolerance reactions. Five pediatric studies were included in our meta-analysis.[ncbi.nlm.nih.gov]
  • "In hypersensitive individuals, fluorides occasionally cause skin eruptions such as atopic dermatitis, eczema or urticaria. Gastric distress, headache and weakness have also been reported.[fluoridealert.org]
  • […] disease Other websites Drug eruptions — Medscape Books about skin diseases See the DermNet NZ bookstore .[dermnetnz.org]
  • […] morphologic findings and triggers for erythema multiforme Distinguish between erythema multiforme and other hypersensitivity reactions in children including serum sickness like reaction and urticaria multiforme Refer patients with serious cutaneous eruptions[aad.org]

Workup

Diagnosis of type1 hypersensitivity involves clinical evaluation, evaluating serum IgE levels and complete blood count, skin testing, allergen specific serum IgE testing, ophthalmic testing, nasal and bronchial challenge and provocative testing. Knowing the details of history of the disease is more important than testing procedures. Details about history include duration and frequency of allergic attacks, identifiable triggering factors, relation to settings, responses to attempted treatments and family history of atopic disorders [7].

Pleural Effusion
  • A chest X-ray showed hazy opacity with prominent reticulation within the upper lung fields bilaterally, right greater than the left with no pleural effusion. Lung computed tomography revealed nonspecific bilateral upper lung opacification.[ncbi.nlm.nih.gov]

Treatment

Treatment of type1 hypersensitivity reactions include administering antihistamine medications after the allergen is eliminated from the body. Severe hypersensitivity reactions would require a therapy that involves oxygen provision for resolving breathing difficulties. Anaphylactic shock will be managed with intravenous fluids to boost blood pressure. Very severe reactions would require hospitalization. Drugs like mast cell stabilizers, H1 blockers, immunotherapy, and anti-inflammatory corticosteroids and leukotriene inhibitors are also used for treating type1 hypersensitivity reactions [8, 9].

Prognosis

Prognosis of type1 hypersensitivity reactions constitute hives, anaphylaxis, swelling and breathing difficulties that usually improve in few minutes to few hours. Some rashes require many days to heal and a vigorous allergic reaction might require an overnight stay in the hospital. Continued exposure to the allergens might require continued medical therapy. Inhaled or ingested allergens may require a few days to get eliminated from the body [6].

Etiology

Allergic or type1 hypersensitivity reactions occur with the interference of IgE. These reactions are caused by opiates, iodinated radiocontrast dye, and vancomycin and appear similar to the urticaria or anaphylaxis. Patients affected by these types of reactions are called Atopic. Atopy is the condition where the patient is genetically predisposed to synthesize IgE antibodies against the allergens.

If allergy is present in a close relative of the patient, then the patient has higher risk of developing allergy. There are no specific causes for allergic hypersensitivity. But, a few reasons are considered as possible causes of this disease. They are pet dander, foods like nuts or shell fish, insect bites, drugs like penicillin or aspirin, some plants and pollen [2]. Relationship between HLA loci and atopy, polymorphism in certain genes that include IgE receptor beta chain, IL-4 receptor alpha chain, CD14, disintegrin are some of the genetic factors that lead to type1 hypersensitivity reactions. Type2 cell-directed immune responses are maintained by the interaction of environmental factors with the genetic factors. The other site specific factors such as adhesion molecules in bronchial epithelium and gastrointestinal tract, and skin, direct the type2 helper cells to the target tissues.

Epidemiology

It has been observed that  individuals affected by atopic diseases have increased from the year 2000 in the United States. Allergic rhinitis is considered the most widespread affecting 17 to 22 percent of the population. It was estimated that Asthma affected nearly 25 million people in the United States in the year 2010. Predominance of asthma has increased from 7.3 percent in 2001 to 8.4 percent in 2010. Asthma affecting 90 percent of children was found to be due to allergy, while 50 to 70 percent of adults were affected by allergic asthma. According to an epidemiological research program, allergic rhinoconjunctivitis was predominant in children in 56 countries [3].

Sex distribution
Age distribution

Pathophysiology

Immediate hypersensitivity reactions are driven by IgE. The development of these antibodies is driven by T and B cells. CD4+ T cells are classified into 3 groups called effector T cells, T-regulatory cells and memory T-cells. Effector T-cells are again classified into T-Helper1, T-Helper 2 and T-Helper 17 depending on the cytokines they produced. Cell-mediated immune response is triggered by TH1 cells. TH2 cells synthesize Interleukin-4 and Interleukin-3 that stimulate B-cells producing antigen specific IgE. T-Helper 17 cells produce a set of interleukins to enhance neutrophil inflammation required for immunity in the skin and mucosa, and to produce antimicrobial peptides. The allergen that is ingested is managed by antigen presenting cell, such as B-cell. These cells later get transferred to lymph nodes appearing as naïve TH cells bearing receptors for a particular antigen [4, 5].

Prevention

People can identify the specific allergens which trigger the inflammatory reaction and learn to avoid them. Types of allergy tests conducted by the specialists include skin testing, blood tests, and checking for the allergic reactions by certain allergens. The identified allergens are then avoided to prevent allergies [10].

Summary

The immune reactions that occur in the human body as protection to the body against diseases can sometimes result in reactions that damage the host itself. These reactions are known as hypersensitivity reactions. Immunopathology is the study of hypersensitivity reactions. There are four mechanisms of hypersensitivity. Type1 is also called immediate hypersensitivity and is IgE-mediated or called common allergy. Type2 reactions are cytotoxic and they are mediated by antibody and cellular mechanisms. Type3 reactions include antigen and antibody complex formations. These complexes attach the red blood cells and help in removing them by phagocytosis, release cytokines, stimulate inflammation in tissue spaces and activate T-cells. Type4 reactions are cell mediated, take more than 12 hours to develop and depend on antigen and T-cell interaction leading to inflammation. Allergy is also a hypersensitivity disorder caused by external antigenic substances. As the types of hypersensitivity vary, the etiology of allergic reactions as example is discussed here [1].  

Patient Information

  • Definition: Hypersensitivity reactions are the immune reactions that arise due to the disease antigens, and damage the cells in the body. These reactions have four different types of mechanisms in managing immunity against the ingested foreign particle. 
  • Cause: Some of the causes of type1 hypersensitivity reactions include genetic factors, environmental factors and site specific factors like adhesion molecules to bronchial epithelium and gastrointestinal tract. Genetic factors include HLA loci and polymorphism in some genes. Environmental factors include endotoxins, viral and bacterial infections that usually hinder T-helper2 cells and discourage allergic responses.
  • Symptoms: Some of the symptoms of type1 hypersensitivity are nasal congestion, sneezing, wheezing, rashes, hives and itchy eyes. 
  • Diagnosis: Diagnostic tests for type1 hypersensitivity include skin testing, serum IgE testing, ophthalmic testing, provocative testing, and nasal and bronchial challenge. 
  • Treatment:Treatment of this disease includes use of antihistamines and administering intravenous fluids to enhance blood flow in the anaphylactic shocks. The drugs used for treating severe disease are H1 blockers, anti-inflammatory corticosteroids, immunotherapy, mast cell stabilizers and leukotriene inhibitors. 

References

Article

  1. Lawlor GJ, Fischer TJ, Adelman DC, eds. Manual of Allergy and Immunology. 3rd ed. Philadelphia, Pa: Lippincott-Raven; 1995.
  2. Birnbaum J, Vervloet D. Allergy to muscle relaxants. Clin Rev Allergy 1991; 9:281.
  3. Schoenwetter WF. Allergic rhinitis: epidemiology and natural history. Allergy Asthma Proc. Jan-Feb 2000;21(1):1-6.
  4. Middleton E, Reed C, Ellis E, eds. Allergy: Principles and Practice. 5th ed. St. Louis, Mo: Mosby-Year Book; 1998.
  5. Pichler WJ. Delayed drug hypersensitivity reactions. Ann Intern Med 2003; 139:683.
  6. Janson C, Anto J, Burney P, et al. The European Community Respiratory Health Survey: what are the main results so far? European Community Respiratory Health Survey II. Eur Respir J. Sep 2001;18(3):598-611.
  7. Bernstein JA, Lang DM, Khan DA, Craig T, Dreyfus D, Hsieh F, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. May 2014;133(5):1270-7
  8. Stock P, DeKruyff RH, Umetsu DT. Inhibition of the allergic response by regulatory T cells. Curr Opin Allergy Clin Immunol. Feb 2006;6(1):12-6.
  9. Weber RW. Immunotherapy with allergens. JAMA. Dec 10 1997;278(22):1881-7.
  10. Lasley MV. Allergic disease prevention and risk factor identification. Immunol Allergy Clin North Am. 1999;19:149-59.

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Last updated: 2018-06-22 08:52