Which condition is classified under Type 1 hypersensitivity reaction?

Type 1 hypersensitivity reactions are immediate allergic responses that occur when an individual is sensitized to an allergen. Upon subsequent exposure to the same allergen, the immune system quickly reacts by releasing immunoglobulin E (IgE) antibodies. This leads to the release of histamine and other chemicals from mast cells and basophils, resulting in symptoms such as swelling, redness, and difficulty breathing.

Anaphylaxis is a severe and potentially life-threatening form of Type 1 hypersensitivity. It manifests after exposure to allergens such as certain foods, medications, or insect stings, triggering a rapid and extreme reaction that requires immediate medical intervention. The characteristics of this reaction, such as its quick onset and reliance on IgE and mast cell activation, clearly categorize anaphylaxis within the realm of Type 1 hypersensitivity.

Other conditions listed, including rheumatoid arthritis, systemic lupus erythematosus, and Parkinson's disease, do not fit this classification. Instead, they are associated with other types of immune responses, such as autoimmune reactions or degenerative processes, rather than immediate hypersensitivity reactions driven by IgE.