Hypersensitive

Hypersensitive refers to an exaggerated response by the immune system to a particular substance, known as an allergen. This condition is commonly associated with allergies, where the body reacts to normally harmless substances such as pollen, dust mites, or certain foods.

Types of Hypersensitivity

Hypersensitivity reactions are classified into four types, known as Gell and Coombs classification:

• Type I Hypersensitivity (Immediate Hypersensitivity): This type involves IgE antibodies and is typically associated with allergic reactions such as anaphylaxis, asthma, and hay fever.
• Type II Hypersensitivity (Cytotoxic Hypersensitivity): This type involves IgG or IgM antibodies and can lead to conditions such as hemolytic anemia and Goodpasture's syndrome.
• Type III Hypersensitivity (Immune Complex-Mediated Hypersensitivity): This type involves the formation of immune complexes that can cause conditions like systemic lupus erythematosus and rheumatoid arthritis.
• Type IV Hypersensitivity (Delayed-Type Hypersensitivity): This type is mediated by T cells and is associated with conditions such as contact dermatitis and tuberculosis.

Symptoms

The symptoms of hypersensitivity can vary widely depending on the type and severity of the reaction. Common symptoms include:

• Itching
• Swelling
• Rash
• Shortness of breath
• Anaphylaxis

Diagnosis

Diagnosis of hypersensitivity typically involves a combination of medical history, physical examination, and specific tests such as skin prick tests, blood tests for specific IgE antibodies, and patch tests.

Treatment

Treatment for hypersensitivity reactions may include:

• Antihistamines
• Corticosteroids
• Epinephrine (for severe reactions)
• Immunotherapy (allergy shots)

Prevention

Preventive measures include avoiding known allergens, using air purifiers, and following a hypoallergenic diet if food allergies are present.

See Also

• Allergy
• Immune system
• Anaphylaxis
• Asthma
• Autoimmune disease