Hypersensitivity reaction

Hypersensitivity reaction is a condition where the body's immune system reacts abnormally to a foreign substance. This reaction can be immediate or delayed, and can range from mild to severe. Hypersensitivity reactions are classified into four types: Type I, Type II, Type III and Type IV.

Type I Hypersensitivity

Type I hypersensitivity, also known as immediate hypersensitivity, is characterized by the production of IgE antibodies in response to an allergen. This type of hypersensitivity reaction is commonly associated with allergies such as hay fever, asthma, and food allergies.

Type II Hypersensitivity

Type II hypersensitivity, also known as cytotoxic hypersensitivity, involves the destruction of the body's own cells. This can occur when the immune system mistakenly identifies normal body cells as foreign. This type of hypersensitivity reaction is commonly associated with conditions such as rheumatic fever and Goodpasture's syndrome.

Type III Hypersensitivity

Type III hypersensitivity, also known as immune complex hypersensitivity, involves the formation of immune complexes that can deposit in various tissues and cause inflammation. This type of hypersensitivity reaction is commonly associated with conditions such as systemic lupus erythematosus and rheumatoid arthritis.

Type IV Hypersensitivity

Type IV hypersensitivity, also known as delayed-type hypersensitivity, is mediated by T cells rather than antibodies. This type of hypersensitivity reaction is commonly associated with conditions such as tuberculosis and contact dermatitis.

See Also

• Allergy
• Immunology
• Autoimmune diseases

References

Hypersensitivity reaction Resources
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