Hypersensitivity

For other uses, see Hypersensitivity (disambiguation).

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Hypersensitivity

Other names: Hypersensitivity reaction, intolerance
Specialty| Immunology

Hypersensitivity refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune system and these reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized (immune) state of the host. The Gell and Coombs classification of hypersensitivity is the most widely used, and distinguishes four types of immune response which result in bystander tissue damage.[1]

## Contents

* 1 Coombs and Gell classification
* 2 Notes
* 3 References
* 4 External links

## Coombs and Gell classification[edit | edit source]

Immunologic aspects of hypersensitivity reactions  Type | Alternative names | Antibodies or Cell Mediators | Immunologic Reaction | Often mentioned disorders | Videos

|
|
|
|
|

I |

* Allergy
* Immediate
* Anaphylactic

* Antibody IgE

| Fast response which occurs in minutes, rather than multiple hours or days. Free antigens cross link the IgE on mast cells and basophils which causes a release of vasoactive biomolecules. Testing can be done via skin test for specific IgE.[2] |

* Atopy
* Anaphylaxis
* Asthma
* Churg-Strauss Syndrome

Video explanation of type I hypersensitivity

II |

* Cytotoxic,
* Antibody-dependent

* Antibody IgM
* Antibody IgG
* Complement
* MAC

| Antibody (IgM or IgG) binds to antigen on a target cell, which is actually a host cell that is perceived by the immune system as foreign, leading to cellular destruction via the MAC. Testing includes both the direct and indirect Coombs test.[3] |

* Autoimmune hemolytic anemia
* Rheumatic heart disease
* Thrombocytopenia
* Erythroblastosis fetalis
* Goodpasture's syndrome
* Graves' disease[note 1]
* Myasthenia gravis[note 1]

Video explanation of type II hypersensitivity

III |

* Immune complex

* Antibody IgG
* Complement
* Neutrophils

| Antibody (IgG) binds to soluble antigen, forming a circulating immune complex. This is often deposited in the vessel walls of the joints and kidney, initiating a local inflammatory reaction.[4] |

* Serum sickness
* Rheumatoid arthritis
* Arthus reaction
* Post streptococcal glomerulonephritis
* Membranous nephropathy
* Reactive arthritis
* Lupus nephritis
* Systemic lupus erythematosus
* Extrinsic allergic alveolitis (hypersensitivity pneumonitis)

Video explanation of type III hypersensitivity

IV |

* Delayed,[2][3]
* cell-mediated immune memory response,
* Antibody-independent

| Cells

* T-cells

| T helper cells (specifically Th1 cells) are activated by an antigen presenting cell. When the antigen is presented again in the future, the memory Th1 cells will activate macrophages and cause an inflammatory response. This ultimately can lead to tissue damage.[5] |

* Contact dermatitis, including Urushiol-induced contact dermatitis (poison ivy rash).
* Mantoux test
* Chronic transplant rejection
* Multiple sclerosis[6]
* Coeliac disease
* Hashimoto's thyroiditis
* Granuloma annulare

Video explanation of type IV hypersensitivity

V  |

* Autoimmune

* IgM or IgG
* Complement

This is an additional type that is sometimes (especially in the UK) used as a distinction from Type 2.[7]

Instead of binding to cell surfaces, the antibodies recognise and bind to the cell surface receptors, which either prevents the intended ligand binding with the receptor or mimics the effects of the ligand, thus impairing cell signaling.[citation needed]

* Graves' disease
* Myasthenia gravis

## Notes[edit | edit source]

1. ↑ 1.0 1.1 See type V explanation in table.

## References[edit | edit source]

1. ↑ "Davidson's Principles and Practice of Medicine, IE Edition, 20th Ed: Medicine—Clinical Medicine". Journal of Endocrinology, Metabolism and Diabetes of South Africa. 13 (2): 75–75. July 2008. doi:10.1080/22201009.2008.10872174. ISSN 1608-9677. Archived from the original on 2021-08-28. Retrieved 2020-02-13.
2. ↑ 2.0 2.1 Black, C. A. (1999). "Delayed type hypersensitivity: Current theories with an historic perspective". Dermatology Online Journal. 5 (1): 7. PMID 10673450. Archived from the original on 2015-06-11. Retrieved 2015-05-15.
3. ↑ 3.0 3.1 Delayed Hypersensitivity Reactions at eMedicine
4. ↑ Kumar, Vinay; Abbas, Abul K.; Aster, Jon C., eds. (2014). "Hypersensitivity: Immunologicaly Mediated Tissue Injury". Robbins & Cotran Pathologic Basis of Disease (9th ed.). Elsevier Health Sciences. pp. 200–11. ISBN 978-0-323-29635-9. `{{cite book}}`: `|access-date=` requires `|url=` (help); `|archive-url=` requires `|url=` (help); Unknown parameter `|chapterurl=` ignored (help)
5. ↑ Le, Tau. First Aid for the USMLE Step 1 2013, p. 203-204
6. ↑ Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). "Table 5-1". Robbins Basic Pathology (8th ed.). Philadelphia: Saunders. ISBN 1-4160-2973-7.
7. ↑ Rajan, T.V. (2003). "The Gell–Coombs classification of hypersensitivity reactions: A re-interpretation". Trends in Immunology. 24 (7): 376–9. doi:10.1016/S1471-4906(03)00142-X. PMID 12860528.

## External links[edit | edit source]

Classification|

* ICD-10: T78.4
* ICD-9-CM: 995.3
* MeSH: D006967
* DiseasesDB: 28827

|

* v
* t
* e

Consequences of external causes

Temperature|

| Elevated|

Hyperthermia
Heat syncope

|

Reduced|

Hypothermia
Immersion foot syndromes

Trench foot
Tropical immersion foot
Warm water immersion foot
Chilblains
Frostbite
Aerosol burn
Cold intolerance
Acrocyanosis
Erythrocyanosis crurum

Radiation|

Radiation poisoning
Radiation burn
Chronic radiation keratosis
Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy
Radiation acne
Radiation-induced cancer
Radiation recall reaction
Radiation-induced erythema multiforme
Radiation-induced hypertrophic scar
Radiation-induced keloid
Radiation-induced morphea

Air|

* Hypoxia/Asphyxia
* Barotrauma
* Aerosinusitis
* Decompression sickness
* High altitude
* Altitude sickness
* Chronic mountain sickness
* Death zone
* HAPE
* HACE

Food|

* Starvation

Maltreatment|

* Physical abuse
* Sexual abuse
* Psychological abuse

Travel|

* Motion sickness
* Seasickness
* Airsickness
* Space adaptation syndrome

Adverse effect|

* Hypersensitivity
* Anaphylaxis
* Angioedema
* Allergy
* Arthus reaction

* Adverse drug reaction

Other|

* Electrical injury
* Drowning
* Lightning injuries

Ungrouped
skin conditions
resulting from
physical factors|

* Dermatosis neglecta
* Pinch mark
* Pseudoverrucous papules and nodules
* Sclerosing lymphangitis
* Tropical anhidrotic asthenia
* UV-sensitive syndrome

environmental skin conditions
Electrical burn
frictional/traumatic/sports

Black heel and palm
Equestrian perniosis
Jogger's nipple
Pulling boat hands
Runner's rump
Surfer's knots
Tennis toe
Vibration white finger
Weathering nodule of ear
Wrestler's ear
Coral cut
Painful fat herniation
Uranium dermatosis

iv use

Skin pop scar
Skin track
Slap mark
Pseudoacanthosis nigricans
Narcotic dermopathy

* v
* t
* e

Lymphoid and complement disorders causing immunodeficiency

Primary|

| Antibody/humoral
(B)|

| Hypogammaglobulinemia|

* X-linked agammaglobulinemia
* Transient hypogammaglobulinemia of infancy

|

Dysgammaglobulinemia|

* IgA deficiency
* IgG deficiency
* IgM deficiency
* Hyper IgM syndrome (1
* 2
* 3
* 4
* 5)
* Wiskott–Aldrich syndrome
* Hyper-IgE syndrome

Other|

* Common variable immunodeficiency
* ICF syndrome

T cell deficiency
(T)|

* thymic hypoplasia: hypoparathyroid (Di George's syndrome)
* euparathyroid (Nezelof syndrome
* Ataxia–telangiectasia)

peripheral: Purine nucleoside phosphorylase deficiency

* Hyper IgM syndrome (1)

Severe combined
(B+T)|

* x-linked: X-SCID
autosomal: Adenosine deaminase deficiency
* Omenn syndrome
* ZAP70 deficiency
* Bare lymphocyte syndrome

Acquired|

* HIV/AIDS

Leukopenia:
Lymphocytopenia|

* Idiopathic CD4+ lymphocytopenia

Complement
deficiency|

* C1-inhibitor (Angioedema/Hereditary angioedema)
* Complement 2 deficiency/Complement 4 deficiency
* MBL deficiency
* Properdin deficiency
* Complement 3 deficiency
* Terminal complement pathway deficiency
* Paroxysmal nocturnal hemoglobinuria
* Complement receptor deficiency

* v
* t
* e

Hypersensitivity and autoimmune diseases

Type I/allergy/atopy
(IgE)|

| Foreign|

* Atopic eczema
* Allergic urticaria
* Allergic rhinitis (Hay fever)
* Allergic asthma
* Anaphylaxis
* Food allergy
* common allergies include: Milk
* Egg
* Peanut
* Tree nut
* Seafood
* Soy
* Wheat
* Penicillin allergy

|

Autoimmune|

* Eosinophilic esophagitis

Type II/ADCC

*     * IgM
* IgG

| Foreign|

* Hemolytic disease of the newborn

|

Autoimmune|

| Cytotoxic|

* Autoimmune hemolytic anemia
* Immune thrombocytopenic purpura
* Bullous pemphigoid
* Pemphigus vulgaris
* Rheumatic fever
* Goodpasture syndrome
* Guillain–Barré syndrome

|

"Type V"/receptor|

* Graves' disease
* Myasthenia gravis
* Pernicious anemia

Type III
(Immune complex)|

| Foreign|

* Henoch–Schönlein purpura
* Hypersensitivity vasculitis
* Reactive arthritis
* Farmer's lung
* Post-streptococcal glomerulonephritis
* Serum sickness
* Arthus reaction

|

Autoimmune|

* Systemic lupus erythematosus
* Subacute bacterial endocarditis
* Rheumatoid arthritis

Type IV/cell-mediated
(T cells)|

| Foreign|

* Allergic contact dermatitis
* Mantoux test

|

Autoimmune|

* Diabetes mellitus type 1
* Hashimoto's thyroiditis
* Multiple sclerosis
* Coeliac disease
* Giant-cell arteritis
* Postorgasmic illness syndrome
* Reactive arthritis

GVHD|

* Transfusion-associated graft versus host disease

Unknown/
multiple|

| Foreign|

* Hypersensitivity pneumonitis
* Allergic bronchopulmonary aspergillosis
* Transplant rejection
* Latex allergy (I+IV)

|

Autoimmune|

* Sjögren syndrome
* Autoimmune hepatitis
* Autoimmune polyendocrine syndrome
* APS1
* APS2
* Autoimmune adrenalitis
* Systemic autoimmune disease

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