II. Definitions

  1. Gell and Coombs Classification of Hypersensitivity Reaction
    1. Categories of Hypersensitivity Response

III. Types: 1 - Immediate Hypersensitivity Reaction

  1. Mediated by IgE Antibody to specific antigens
    1. Mast cells stimulated and release histamine
  2. Reaction within one hour of exposure
  3. Examples
    1. Anaphylaxis (e.g. Penicillin)
    2. Urticaria
    3. Angioedema
    4. Anaphylactoid Reaction (e.g. Anaphylactoid Reaction to Radiocontrast)
    5. Atopic Allergy

IV. Types: 2 - Cytotoxic Antibody Reaction

  1. Mediated by IgG and IgM to specific antigens
  2. Examples
    1. Transfusion Reaction
    2. Rhesus Incompatibility (Rh Incompatibility)
    3. Mycoplasma pneumoniae related cold agglutinins
    4. Hashimoto's Thyroiditis
    5. Goodpasture's Syndrome
    6. Delayed transplant graft rejection

V. Types: 3 - Immune Complex Reaction

  1. Antigen-Antibody complexes deposit in tissue
  2. Reaction within 1-3 weeks after exposure
  3. Examples
    1. Systemic Lupus Erythematosus
    2. Erythema Nodosum
    3. Polyarteritis Nodosa
    4. Arthus Reaction (e.g. Farmer's Lung)
    5. Rheumatoid Arthritis
    6. Elephantiasis (Wuchereria bancrofti reaction)
    7. Jarisch-Herxheimer Reaction
    8. Serum Sickness

VI. Types: 4 - Delayed-Type Hypersensitivity

  1. Mediated by T-Lymphocytes to specific antigens
    1. Involves major histocompatibility complex (MHC)
    2. Reaction within 2-7 days after exposure
  2. Examples
    1. Mantoux Test (PPD)
    2. Allergic Contact Dermatitis (e.g. Nickel allergy)

VII. Types: Other allergy mediated reactions

  1. Stimulatory Hypersensitivity
    1. Humoral Antibody activates receptor sites
    2. Example: Thyrotoxicosis (TSH autoantibodies)
  2. Fas/Fas Ligand-induced apoptosis
    1. Example: Stevens Johnson Syndrome
  3. T-Cell activation
    1. Example: Sulfonamide induced Morbilliform rash

VIII. References

  1. Roitt (1988) Essential Immunology, Blackwell,p. 193-214
  2. Riedl (2003) Am Fam Physician 68:1781-90 [PubMed]

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Ontology: Hypersensitivity (C0020517)

Definition (ICF) Functions of the body's response of increased sensitization to foreign substances, such as in sensitivities to different antigens.
Definition (ICF-CY) Functions of the body's response of increased sensitization to foreign substances, such as in sensitivities to different antigens.
Definition (GO) An inflammatory response to an exogenous environmental antigen or an endogenous antigen initiated by the adaptive immune system. [GOC:jal, ISBN:0781735149]
Definition (MEDLINEPLUS)

An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are

Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.

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. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.

NIH: National Institute of Allergy and Infectious Diseases

Definition (SCTSPA) Reacciones alérgicas conocidas a una(s) sustancia(s) en particular
Definition (SNOMEDCT_US) Known to have allergic reactions to particular substance(s)
Definition (SNOMEDCT_US) A pathological process initiated by exposure to a defined stimulus at a dose tolerated by normal persons. It may be the manifestation of a disposition to hypersensitivity.
Definition (SCTSPA) Proceso patológico iniciado por la exposición a un estímulo definido, en una dosis que toleran las personas normales. Puede ser la manifestación de una disposición a la hipersensibilidad.
Definition (NCI) An immune response that occurs following exposure to an innocuous antigen, but that does not require the presence of preformed antibodies to the antigen.
Definition (NCI_FDA) Hypersensitivity; a local or general reaction of an organism following contact with a specific allergen to which it has been previously exposed and to which it has become sensitized.
Definition (NCI_NCI-GLOSS) An exaggerated response by the immune system to a drug or other substance.
Definition (MSH) Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.
Definition (CSP) state of previously immunized body in which tissue damage results from the immune response to a further dose of antigen.
Definition (HL7V3.0) <p>Hypersensitivity to an agent caused by an immunologic response to an initial exposure</p>
Concepts Pathologic Function (T046)
MSH D006967
ICD10 T78.4 , T78.40
SnomedCT 421961002, 106190000, 274211000, 418168000, 418925002, 157758001, 212998004, 127072000, 157754004, 257550005, 269284003, 269432007, 421668005, 91232002, 212999007, 282092005, 21957007, 418634005
LNC LP7756-2, LP31625-4, LP20697-6, MTHU020822, LA17771-9
English Allergic reaction, Allergy, Hypersensitivities, Allergy, unspecified, Hypersensitivity reaction, Allergy (disorder), Hypersensitivity reaction (disorder), HYSN, Allergic disorder, Allergic reaction NOS, Allergy disorder, hypersensitivity, hypersensitivity (symptom), allergic reaction, allergic reaction (diagnosis), Allergic reaction (NOS), Reaction allergic (NOS), Allergy NOS, Hypersensitivity NOS, Hypersensitivity reaction (NOS), Reaction hypersensitivity (NOS), Hypersensitivity symptom, Hypersensitivity reactions, Allergic reactions, Hypersensitivity [Disease/Finding], ALLERGY, Allergy., allergy, allergy disorders, hypersensitivity reactions, allergic disorder, allergic disorders, hypersensitivity symptoms, hypersensitivity symptom, allergies, allergic reactions, hypersensitivities, hypersensitivity reaction, Allergic disorders, Allergic state (disorder), Allergic reaction NOS (disorder), Disorder due to allergic reaction, Disorder due to allergic reaction (disorder), (Allergy, unspecified) or (hypersensitivity NOS), Allergic disorder (disorder), Allergy, unspecified (disorder), Allergic reaction (disorder), Immune hypersensitivity disorder (disorder), Disorder due to immune hypersensitivity reaction, (Allergy, unspecified) or (hypersensitivity NOS) (disorder), Immune hypersensitivity reaction (disorder), Immune hypersensitivity disorder, Hypersensitivity (finding), Allergic state, Hypersensitivity (qualifier value), Atopic AND/OR hypersensitivity state, Hypersensitivity, Allergies, Hypersensitivity Reaction, ALLERGIC REACTION, HYPERSENSITIVITY, Allergy/allergic reaction nos, hypersensitivity; reaction, allergic; reaction, reaction; allergic, reaction; hypersensitivity, Allergic reaction, NOS, Allergic state, NOS, Allergy, NOS, Hypersensitivity reaction, NOS, Allergic Disorders, Allergic reaction to substance, Allergic reaction to substance (disorder)
French HYPERSENSIBILITE, ALLERGIE, Réaction d'hypersensibilité, Réaction allergique, Allergie SAI, Hypersensibilité SAI, Réaction allergique SAI, Réaction d'hypersensibilité SAI, HYSN, Symptôme d'hypersensibilité, REACTION ALLERGIQUE, Allergie, Hypersensibilité
Portuguese HIPERSENSIBILIDADE, ALERGIA, Sintoma de hipersensibilidade, Reacção alérgica NE, Reacção alérgica, Hipersensibilidade NE, Alergia NE, Reacção de hipersensibilidade, Reacção de hipersensibilidade NE, REACCAO ALERGICA, Reação Alérgica, Alergia, Hipersensibilidade
Spanish HIPERSENSIBILIDAD, ALERGIA, reacción alérgica a una sustancia (trastorno), reacción alérgica a una sustancia, reacción de hipersensibilidad (trastorno), reacción de hipersensibilidad, Reacción alérgica, Reacción de hipersensibilidad (NEOM), Alergia NEOM, Hipersensibilidad NEOM, Síntoma de hipersensibilidad, Reacción alérgica NEOM, Reación de hipersensibilidad, Reacción de hipersensibilidad, Reacción alérgica (NEOM), alergia (trastorno), REACCION ALERGICA, trastorno de hpersensibilidad inmunológica (trastorno), trastorno de hpersensibilidad inmunológica, hipersensibilidad (hallazgo), trastorno alérgico, reacción alérgica, trastorno alérgico (trastorno), hipersensibilidad (calificador), hipersensibilidad, trastorno por reacción alérgica, reacción alérgica, SAI (trastorno), reacción alérgica, SAI, Allergic reaction NOS, estado atópico Y/O de hipersensibilidad, reacción por hipersensibilidad inmunológica, trastorno debido a reacción alérgica, trastorno de hipersensibilidad inmunológica (trastorno), trastorno de hipersensibilidad inmunológica, trastorno causado por reacción alérgica (trastorno), reacción por hipersensibilidad inmunológica (trastorno), alergia, no especificada, estado alérgico (trastorno), alergia, trastorno causado por reacción alérgica, trastorno por reacción inmunológica por hipersensibilidad, reacción alérgica (trastorno), alergia, no especificada (trastorno), trastorno inmunológico por hipersensibilidad, reacción de hipersensibilidad inmunológica (trastorno), estado alérgico, Reacción Alérgica, Alergia, Hipersensibilidad
German ALLERGIE, allergische Reaktion NNB, Uebersensibilitaetsreaktion, HYSN, Reaktion, allergisch (NNB), Ueberempfindlichkeit NNB, Uebersensibilitaetsreaktion (NNB), allergische Reaktion, allergische Reaktion (NNB), Uebersensibilitaetssymptom, Allergie NNB, ALLERGISCHE REAKTION, Allergie, nicht naeher bezeichnet, HYPERSENSIBILITAET, Ueberempfindlichkeit, Allergie, Hypersensitivität, Überempfindlichkeit
Dutch allergische reactie NAO, reactie allergisch (NAO), overgevoeligheidsreactie, allergische reactie (NAO), overgevoeligheid NAO, overgevoeligheidsreactie (NAO), allergie, reactie overgevoeligheid (NAO), hypersensitiviteitssymptoom, HYSN, allergie NAO, allergische reactie, Allergie/allergische reactie nao, allergisch; reactie, overgevoeligheid; reactie, reactie; allergisch, reactie; overgevoeligheid, Allergie, niet gespecificeerd, overgevoeligheid, Allergie, Overgevoeligheid
Italian Sintomo di ipersensibilità, Reazione da ipersensibilità (non specificata), Allergia, Allergia NAS, Reazione da ipersensibilità, Reazione di ipersensibilità (NAS), Reazione allergica, Reazione allergica (NAS), Reazione allergica NAS, Ipersensibilità NAS, Allergia (Specifica), Ipersensibilità
Japanese アレルギー反応, 過敏症状, 過敏症反応(NOS), 過敏症NOS, アレルギー反応(NOS), アレルギー反応NOS, アレルギーNOS, 過敏症反応, アレルギーNOS, カビンショウハンノウNOS, アレルギーハンノウNOS, カビンショウジョウ, カビンショウハンノウ, カビンショウNOS, カビンショウ, アレルギーハンノウ, アレルギー, アレルギー, 過敏症
Swedish Överkänslighet
Finnish Yliherkkyys
Czech Reakce přecitlivělosti, Alergická reakce, Alergie, Přecitlivělost NOS, HYSN, Alergie NOS, Reakce přecitlivělosti (NOS), Přecitlivělost, Alergická reakce NOS, Hypersensitivní syndrom, Alergická reakce (NOS), Hypersensitivní reakce (NOS), alergie, hypersenzitivita, přecitlivělost
Korean 상세불명의 알레르기
Polish Uczulenie, Reakcja alergiczna, Nadwrażliwość, Odczyn alergiczny, Alergia
Hungarian allergiás reakció, allergia k.m.n., Hypersensitivitási tünet, allergiás reakció (k.m.n.), HSYN, Allergiás reakció (k.m.n.), Túlérzékenységi reakció (k.m.n.), Hypersensitivitas k.m.n., Hypersensitivitas, Allergia, Hypersensitiv reakció (k.m.n.), allergiás reakció k.m.n., Hypersensitiv reakció
Norwegian Hypersensitivitet, Overfølsomhet, Allergi